Dallas, his older brother, said, "I can't imagine. He was so secretive in his e-mail. I'm hoping maybe it's a car...maybe cars for all three of us."

I said, "Dal, your brother's only thirteen..."

"Fourteen in three weeks," Austin said.

"Still too young to drive. But knowing my dad as I do, I wouldn't put it past him. He tries to spoil you rotten."

"Well, we are his only grandchildren."

I wish I'd kept that e-mail now. All I remember from it was he had undergone a life-altering experience and material possessions don't mean much to him now. He said he has never felt better in his life, and he wants us to share in his happiness. I was afraid he might've has a stroke or heart attack, but he insists he's in the peak of health for a man in his 60's. And he was going to arrive later tonight.

The boys and I spent the day watching college football - Dallas has his heart set on going to Colorado. I also finished wrapping my father's Christmas present, an autographed first-edition of John LeCarre's "Tinker, Tailor, Soldier, Spy". It cost a pretty penny, but I'd recently won $20,000 on a slot machine in Vegas. I had gotten the boys two dirt bikes.

The doorbell rang at seven while I finished preparing dinner, and when we opened the door to greet my dad all three of our jaws dropped. Facially, he still resembled his old self, with his trim white beard, bald pate, and bifocals. He was often hired to play Santa, not only for his face but also for his husky build.

My dad was no longer husky. A waist even trimmer than my own thirty-four inches was the first thing I noticed, but that made way for all the major changes his body had undergone. He wore a flannel shirt with the sleeves rolled up, and his forearms looked like Popeye's with flecks of white hair and veins snaking around them. Two cannonball arms threatened to split the seams where they met two basketball-sized shoulders. His neck looked thicker than my thigh, and his shirt was partially unbuttoned where more tufts of white hair grew across a chest that stuck so far out he looked like he would pitch forward any moment. The crevice in his chest looked so deep it could hide my present.

"Done gawking, or aren't you gonna invite your old man in?" His voice sounded deeper than ever, and something else...his tone, the way he used his voice, it sounded...sexy.

The three of us moved out of the way as dad turned his body sideways in order to enter; even then, his pecs nearly touched the door jamb. His jeans made a swishing sound as he walked with two gigantic thighs rubbing with each step.

My father stood in the living room after setting down his bags, put his hands on his hips, and said, "So, whaddya think, boys?"

Austin said, "Grampa Walt, you're...wow!"

Dallas said, "It's kinda weird, but kinda cool at the same time."

"Thanks, boys, it's definitely cool. What about you, Grant? Like my big surprise?" He flexed his arm, and the seam burst. "Darn it, another one popped. Just don't make 'em like they used to." His smile was almost a leer.

I really didn't know what to say, and I finally stammered, "I...I guess if you...you like what you did to...aw, geez, dad, what happened? What did you do to yourself?"

Dallas said, "I think I know dad, cuz my science teacher, Mr. Hughes, looks the same way Grampa does. Everyone calls him Mr. Huge now. You bought some MassX, didn't you?"

My father laughed. "Damn, but you're smart. Right on the nose, you are."

"MassX? What the heck is that?" I must not be up on steroids.

Dallas said, "I saw it on an infomercial once. It's supposed to be some nutritional supplement or something that grows your muscles in thirty minutes to maximum volume. They showed this guy actually growing after he'd taken it, and he got as big as Grampa. It was like watching 'The Incredible Hulk', 'cept he didn't get angry or turn green. And the announcer said not every body will grow, so anyone who doesn't gets their money back."

"And as you see by my results, it worked perfectly on me. I'm telling you, I've never felt better in my whole life. You can't imagine what it feels like to go into a gym, bench press half a ton, leg press a full ton, and not even break a sweat. My heart rate is back to normal, my lungs are healthy again, and now when I shower and I can't see my toes I know it's because of this powerful chest instead of a bloated belly. And speaking of bellies, is dinner ready? Sure smells delicious."

I didn't have to worry about leftovers, as dad ate half the ham, heaps of mashed potatoes with gravy, several glasses of Coke, and almost the entire apple pie. Dad was always a hearty eater, even more so now, but watching him down so much food rattled me. My boys loved it, though, and urged him to eat more.

"As much as I'd love to, I'm afraid we'll have to stop here. We've got a big day ahead of us, and I've a feeling I'm going to need as much strength as possible."

"That's right, boys, no need to tucker him out." My sons ran into the other room to watch MTV after they put their dishes in the sink, and I said, "Uh, dad, considering what's...well, now that you're...I mean, would you rather sleep on my bed instead of the guest bed? It's a king, and the guest bed is a full. I'll sleep on that one, I can't imagine you would be comfortable on it."

"Well, that's nice of you son, thanks. Listen, now that the boys are out of the room, I wanna let you in on a secret." Dad leaned in. "MassX has made me into a new man in more ways than one. My sex drive has increased tremendously, so much so that...I did a porn movie!"

"DAD!" My conservative, church-going father having sex with some strange woman on film? This was too much.

"And I was so popular on the set that I'm going to be in another one that starts filming after the new year. Grant, you would be amazed how good it feels to be so potent with masculinity. I am a changed man, and I wouldn't go back to my old self ever. I hope you're happy for me."

"Dad, if it makes you happy, then I'm happy too. But, really dad, a porn movie?"

"It didn't start out that way. I did a little modeling after I'd taken the MassX, and some of it was nude. Word got around about some old man in his sixties with a godlike body, and soon I get this offer to make a porn movie, and I figured you only live once. And when the cameras started rolling, it was just as big a thrill as when I took MassX. I was the center of attention with my big muscles, and I loved it."

That night I had trouble sleeping as the image of my father in front of a camera having sex with some girl barely older than Dallas kept popping up. Could he have hurt her with his weight on top of her, or could she have taken something too. Was there MassX for women? It's no wonder he was popular; I had to admit that even though his muscles were freakish, he looked better than since before Mom died six years ago.

I awoke the next morning to a booming "Merry Christmas, ho, ho, ho" from my dad, and then I heard Austin yell, "Wow, Santa, you've sure changed since last year!" Dad always dressed as Santa for them, and even when they knew it was him they continued play acting. Then I'd walk in and say, "Told you he's for real." Then after we'd all drunk a glass of eggnog he'd pass around the presents and we'd open his as if Santa knew what Grampa wanted.

I wasn't sure how dad would alter his costume to fit his new body, but I never expected him to look like the man I saw after I walked into the living room. About the only things he still wore that could still fit him were the red-and-white hat and his calf-highs boots. He stood there shirtless, and for the first time I saw how massive his muscles were. His white fur lay dense upon his tanned body, and his hard nipples pointed downward from a Herculean chest. His shoulders looked like basketballs split in half, his arms the size of bowling balls, the forearms as big as a football! His abs were shredded into an 8-pack that had to be strong enough to support his top half.

Below his waist he wore red spandex gym shorts with white fur around the waistband and legbands. A pair of huge glutes threatened to burst from the back. One thigh alone looked as big as Austin's chest, and one calf looked like it could feed a small dinner table. And no wonder he was in a porn movie; his huge genitalia threatened to burst from the front. His dick reached down to just above the left legband. Part of me wanted to yell at him for such an obscene display in front of my boys, the rest of me understood why he wanted to show off his new body.

"Told you he's for real," I said, resigning myself to dad's new form.

"More real than ever," Santa-dad said, flexing his mighty right arm. "Santa found it harder than ever to haul all those presents, so he started working out, and look at these results." He began posing like a bodybuilder, and my boys egged him on with cheers and whistles. Even I got into the act, and he loved the attention.

After he finished, he said, "Now we've got one more thing to do before we open our presents. Let me get Santa's famous eggnog, straight from the North Pole!"

Once he'd left the room, Austin said, "Wow, Grampa's really hung!"

"Austin!"

Dallas said, "Well, dad, he is. Mr. Hughes has one about that big, and sometimes in class he'll purposely start popping a boner down his pants to gauge our reaction. We're pretty used to that now. He loves his muscles so much I'm surprised he can teach us anything."

"Yeah," I said, "dad sure loves his new muscles, too. But at least he's retired so he doesn't disturb anyone at work."

"I'll bet he's gonna have lots of lady friends now."

Yeah, I thought, and they're all gonna be in his movies.

Santa-dad walked back in holding a tray with four frosted glasses of eggnog on it; each had our names etched on it. He handed them to each of us, and we clinked them as we each said, "Cheers." The boys drank theirs quickly, while I savored the rum added into mine. I thought I tasted something different; maybe dad accidentally put cloves instead of nutmeg into it.

Austin said, "Okay, Santa, we were very good this year. What did you bring us?"

Santa-dad said, "Not yet, your father hasn't finished his nog." I drank the rest of mine in one big gulp.

Dallas said, "Okay, now it's time to unwrap our presents."

Santa-dad smiled. "Actually, boys, I've already given you one of my presents, and it's going to unwrap you!"

I asked, "What do you mean by that?" Then I heard a moan, and I saw Austin rubbing his chest.

Austin said, "Oh, I feel a wicked case of heartburn." Then his brother said, "Yeah, I'm feeling it too."

Dad said, "That's what I thought it was, but I found out it's your stomach muscles growing after they've been hit with a dose of MassX, like the doses in your eggnog."

"What!" I was about to stand when the feeling he just described hit me, and I fell back in my chair with a grunt.

"Merry Christmas, men. See, I figured if this worked on me, and it's similar to Rogaine, then it should work on any man with my genetic material floating around in them. In other words, my son and my two grandsons. I'm glad to see my theory held up, and now I'll have the pleasure of watching all of you turn into brawny, beefy, musclebound studs like myself in less than thirty minutes. Why, it's already working on Austin and Dallas! Tell me, boys, doesn't it feel good?"

"Mm, this isn't good, it's great! Hey, my voice changed. Wow, listen to it; it sounds so deep." I couldn't believe what I heard from Austin's mouth. He now sounded like Arnold Schwarzenegger with a Midwest accent. Arnold...my boy's gonna end up bigger than him. And so am I.

Oh, yeah, so am I! Wait, I don't want this. Dad tricked us into drinking it...is there any antidote? Probably not. Does this wear off? God, I hope so. I can't imagine having a huge body all the time. What would the guys at work say? Shit, my postal carrier uniform won't fit me anymore, I'll just be bulging out all over the place. I looked down to see if it was affecting me, and I saw my chest slowly but surely rising inside my pajama top. Already starting to bulge. I ran my hands around the heavy curve of muscle; my nipples had hardened. An involuntary moan escaped my lips as I pinched each of them.

"That's right, son. Nothing can match the feeling of muscle and testosterone pumping through your veins. It's with me every minute of the day, and now all three of you can share it with me."

"Oh, Grampa, yeah!" Dallas said. "Mr. Hughes always talks about it, and I can't wait to see the look on his face when I walk into class with all these muscles. His jaw's gonna drop to the floor. Oh, man, I need to stand up; there's no room in this chair for me to grow." He stood up, and I saw how tight his pajamas had gotten on him as his muscles stretched every inch of cloth from his shoulders to his calves. His face had changed, as his jaw grew squarer and his cheeks sunk like some kind of supermodel's. Some thick stubble, like a three-day-old beard, appeared on his face, making his modelish looks stronger. His lips puffed with fullness, giving him a sexy pout.

Sexy? What am I thinking? That's my son; I can't think of him as sexy. But I can't deny how much better looking he is in just those few short minutes since he took MassX. I looked at Austin, to see how he'd changed...oh my God! And dad was looking at him too wide-eyed.

I don't know if it's because of his age, but the MassX was working overtime on him. He didn't have stubble, he had a full beard on his teen face, and thick chest hair oozed out from every hole in his pajama top where the buttons were weakening their grip. He breathed in, and POP POP POP went the top three buttons; one of them broke an ornament on the tree. "Ooh, yeah," he moaned in that deep voice, "I'm gonna shred these pj's up with all my new muscle." He flexed his left arm and RIIIP went the sleeve as the peak of his bicep popped up like toast. He did the same with his right arm, but this time more slowly as the cloth agonized until it could no longer hold his mighty arm inside. RIIIP! He smiled mischievously. "Guess I'm not a little boy anymore, huh, dad?" He took the remains of his top and tore the rest off until he stood topless in front of us, his muscles still growing as veins snaked all over them.

Another series of pops alerted us to Dallas' growing body as his mighty chest, though not nearly as hairy as his brother's, crowded out his pajama top. He undid the other buttons and did a slow, tantalizing strip. First he showed one colossal shoulder, shrugging it around, and did the same with the second. He turned his back to us and eased his shirt down so we could see every fiber of his V-shape, the span of muscle equalling my father's width. I even noted the Christmas tree shape in his lower back; how appropriate for this time of year. He turned to face us, his body still in the throes of growth, and said, "Come on, dad, it's your turn to give us a show."

"That's right, Grant. Time to show daddy how much you love your gift." I looked at my dad, but something else caught my eye. I stared at the base of his thighs...sweet Jesus, he had a hardon! A purplish knob the size of a lemon was attached to a shaft at least three inches wide and sticking out past his legband at least six inches. A clear drop of precum oozed from the tip. He was aroused watching my sons growing in front of him, and I felt the strangest thing.

Jealousy. I didn't understand it, but all I could think was if he got this turned on by their show, then I had to give him the best show of all. I didn't want him just to be hard...I wanted to make my father cum! What was wrong with me? But it didn't feel wrong, just so right. All this gigantic, pulchritudinous muscle on me, dad, and my boys belonged on us.

Dad said, "Men, I told your dad last night that I made a porn movie. What I didn't tell him was it was gay, with guys who'd all taken MassX. Yup, your old man got this big dick of his sucked by a musclepup barely older than you, Dallas. And then he begged me to fuck him in his huge, hairy ass. Kept calling me grandad while I pounded him like a jackhammer. Never thought about gay sex til after I got big, and never thought about incest til that guy got me so turned on I shot a load so deep into him it could've dribbled out his lips."

I watched dad slowly stroke his cock as he talked, and the filthy language from his mouth and his huge body and my still-growing one made me lose my last bit of common sense. I stood up quickly and with a sexy growl rent my bottoms from my body. Naked from the waist down, I turned around to show dad my newly muscled glutes. I flexed them for him, and he let go a sigh of approval. "Is this what you like, dad?"

"I love it, son. I love your sexy, muscular, massive ass."

I felt my anal muscles quivering like jelly. "Wanna fuck me, dad? Wanna take your son's cherry ass with your huge daddy fuck tool?"

"Do him, grampa, fuck dad!" My sons started chanting, "Fuck our dad, fuck our dad." I heard another large rip behind me, then a thwack, then two gasps from my sons. I turned to look behind me at the most mouth-watering sight; my dad still wearing the hat and boots, and naked everywhere else sporting the mightiest erection I've ever seen in my life. It rose proudly from his white-haired groin, a pair of gonads the size of peaches (and just as fuzzy) descending halfway down his oaklike thighs. It curved slightly upward, more than two feet long, and veins crisscrossed up and down it. I licked my lips.

Dad's lust-filled eyes bore into mine as he strode towards me, his cock bouncing with each step. I still had my back to him, eagerly awaiting his manhood inside me. He grabbed my bicep which strained against the cloth, spun me around, and kissed me roughly. I responded in kind, opening my mouth and stabbing my tongue into his orifice. He ripped my top off, and I stood nude before him.

"I love you, Grant. I created you with love from the seed of my loins, and I brought you into this world as naked as you are now. I love you so much I recreated you in a new form, and it is time for you to take the seed from my loins."

"Take me, father. Please?" Dad grabbed me under my arms and hoisted me high until my limp but growing cock was in his face. Slowly he lowered me until I felt the head of his schlong at my anus. The precum felt soothing, like a balm, but with one sudden thrust several inches of dad's manhood entered me and hit my prostate. Pain and pleasure flooded me, and I had no idea what I was babbling as he took more and more of my colon.

"Watch this, men," dad said to my sons, who gaped at our display of unabashed homosexual sodomy. They paid so much attention to us that they didn't notice each of their bottoms had torn away to show their newly gargantuan legs or their limp, equine penises. Why were we limp, how come we weren't as hard as dad? I wanted a hard dong in front of dad's face! But my thoughts went away as I watched dad take his arms away from me, leaving me impaled on his cock. Somehow I managed to stay balanced, but then he lowered me til my feet almost touched the ground, and then raised me back up using nothing but the power from his groin. Again and again, faster and faster, I felt like a little boy on his knee getting a horsey ride, but I was a big man getting a ride on dad's horsey cock.

"Please, dad," I cried out, "I wanna cum! Why isn't my dick getting as big and hard as yours?"

"You haven't stopped growing, son. You'll be done in a few minutes. Remember, you finished drinking it up last. In fact, your sons are done now. Just look at what they're doing."

I turned my head and saw my fully-grown sons standing face to face, our should I say cock to mouth. For their now engorged cocks stood away from their hairy, beefy frames travelling upwards until each head met the other brother's lips. A standing 69; would I call it an 11? Or maybe a "W", since their dicks met like crossed swords. I knew one thing to call it: erotic.

A strong thrust from dad focused me back to him. "Soon, son, very soon you'll understand what I'm feeling right now as I'm fucking my own kin. I think you've stopped growing now, 'cuz that dick of yours is riding up my pecs." And it was. Sensation had returned to my cock as it throbbed to life, as long and heavy as my father's with a smaller head. Dad bent forward to kiss it, and shivers of ecstasy raced through me. His pink tongue lapped at the tip, then swirled around it. "Oh, Grant, your cock is...magnificent." He opened his bearded mouth and gently sucked the first few inches of my new manhood. The desire I had for him burned like hell, and I was left speechless except for my grunts and moans. He looked up at me with his ravenous eyes and said, "Cum for me. Cum for daddy, and let me drink from this cock fountain I created for you. Give me your seed, son. Give me the seed of the man I made."

His words zoomed from my ears straight to my cock, which couldn't say no to his order. I keened as jism exploded from my schlong into dad's eager mouth. I watched his Adam's apple bob with every swallow, but soon the eruptions became too much and my cum dribbled onto his whiskers. It was tough to see what was beard and what was cum, so much white. He let go of my cock, which thudded onto my chest, soaking my face and neck as my semen continued shooting from it. I tasted my juice for the first time; like ambrosia for this musclegod.

Dad's pumping turned frenetic. "Aw, Grant, so fuckin' hot. I'm gonna cum. You're gonna feel what your mama felt when I made her pregnant with you. Ah...uh...oh, yeah, feel that?"

"Oh, God, yes! More, sweet Jesus, more. Give me all your seed, daddy. Oh, it's filling my insides. Empty it into me." But dad had so much in his balls that it ended up oozing down my mighty thighs. I was bathed in sweat, semen...and saliva as I felt a pair of tongues lapping up daddy's excess. I looked down and saw my sons eagerly slurping on each leg. I flexed my quads with each vigorous lick. They made their way up to my anus, and when I felt my sons rimming me I almost passed out.

But the sex wasn't over. As with all teenagers, even though they had just cum into each other's mouth, their rampant cocks stood ready for more action. Both were bigger than either dad's or mine; Dallas had about six inches on us, while Austin's incredible cock tower had almost another foot more than that! My thirteen year-old son had to look up in order to see the orange-sized head of his schlong.

"All right, dad," Dallas said with his low, sensuous voice, "Grampa got to take your ass first. So which of your sons do you want to suck first, and which do you want to fuck first?"

How could I decide? Each of them had such big meat, and when they turned around to show me their hairy globes of ass and virgin sphincters I wanted to take both right then and there. Finally, I said, "I can't make up my mind, so you'll decide for me. Rock, paper, scissors between you two. The winner gets my mouth, and I get the loser's ass. But I want both at the same time. Okay?"

They agreed, and on the count of three they showed their hands. Dallas had paper, but Austin's scissors cut it. Austin smiled lewdly and said, "Betcha never thought you'd be sucking my cock on Christmas, huh, dad?"

"Or fucking your brother's hot ass. Go on, Dallas, get on your knees and beg for your father's dick."

Dallas' filthy words got me harder than diamond. "I want it, dad. I want your huge cock so deep inside me you're fucking between my lungs. Your dick's touching my ass, dad. I can tell you're lining up to...oh, shit! Ow, it's so big and fat! You got a whopper of a cock dad, and I want it all."

All I could do was moan as Austin's bigger manhood was now making its way down my throat. My jaw felt like it would unhinge like a snake's as I accepted inch after thick inch of teen meat. Austin reached out and began running his fingers through my hair; his mouth was equally raunchy. "Mm, daddy, you look so good with your lips stretched around my cock like that. Your first blowjob, and you're already a pro." I reached out with my right hand to fondle his nut sac, keeping my left on Dallas' back for leverage. Austin laughed. "Oh, that tickles. Feel how hairy those are. Wasn't much on them before MassX. I'm a hairy, hung, teen stud, and you love that, doncha?"

I nodded as I tried to take more cock, but Austin could only walk so far before Dallas' head would get trapped between those colossal thighs and he'd be gasping for air. But with that cock, it wasn't necessary for him to give me all of it, much as I wanted it. We worked up a steady rhythm, and I saw Dad out of the corner of one eye jerking his tubesteak (a slab of filet mignon to me). Austin, still being a teen despite that musculature, came so quickly down my throat he didn't have time to announce it. But I made sure everyone knew when I was about to blow my wad inside Dallas. My son twitched with every sharp spasm that my cock made as I spewed the same man-milk that created him into him. After the last spurt, I collapsed onto his tabletop-sized back, breathing heavily. I kissed his ear, and he turned so our mouths could meet.

"I love you, father," he said huskily.

"And I love you, son." Our lips pressed gently.

For the rest of the morning, and into early afternoon, the four of us explored every possible form of incestuous muscle-lust until we had accomplished the goal of six orgasms: each of us cumming orally and anally into our other three partners. After that, we were pretty sore and needed cleaning off, so we each took a shower with a partner. Austin and Dallas went together, although we heard them from downstairs begging for each other's cock. When dad and I showered, there was barely enough room for both of us, and with all the lathering of our hairy muscles we soon ended up pec-fucking each other.

When we opened our gifts, the boys were thrilled by the bikes but realized those might not support their huge frames. I still had plenty of money left from the slot win, so I told them I'd make sure to either get them reinforced, or get new ones altogether. Dad loved his book, and I was happy with the deluxe tool chest and work bench as my old one was falling apart. Dad then handed out his presents: complete wardrobes for all three of us in XXXL sizes to fit our massive bodies, along with lots of lycra/spandex gear to show them off to the max. We couldn't help but model for dad, and when I showed off in a pair of teal stretch pants with matching top I felt so damn sexy I wanted to show the world my new body and the proud dick jammed down to my knee. Dad's unexpected gift was the best I'd ever received.

That night, the four of us settled down to watch a new classic: my father's porn movie, "Santa's Muscle Workshop". Watching him take two massive elves on either end reminded me of this afternoon when Austin and Dallas did the same thing. And that night, although no snow was to be seen within fifty miles, the four of us ended up having a very white Christmas all over our MassX'd muscles. •