My day started out like a normal Saturday morning off from work.
I woke up a little early before my alarm had the chance to go off, and I made my way to the bathroom in nothing but my boxers. I lived alone in a two-bedroom apartment, so I didn't have to worry about roommates seeing me or anything.
Not that I would have minded. I turned on the light and saw myself in the mirror. I had fairly large pecs, bulging biceps, and decently shown abs. Speaking of bulges, I had a relatively large one that hung over my meaty thighs. All-in-all, I was a hunk. I stripped the grey boxers off and got into the shower. I got a handful of gel and began washing my body and my hair (I kept it pretty short, nearly buzzed until I was done and began caressing my dick and pumping it with my large hands and big muscles and fantasizing about other bulging men with their lips wrapped around my dick.
When I finished in there, I dried off and walked naked to the kitchen. I had a large breakfast consisting of four eggs, toast, and bacon. To finish it off, I went to the pantry and grabbed a new mass gainer I wanted to try out. The instructions said I should take two tablespoons of the power in a glass of milk.
Truth be told, it was an experimental mass had gotten from a friend who worked in a research lab devoted to enhancing athletic ability and minimizing injury. He was getting his doctorate in biochemistry, and his focus was on increasing the speed at which cells repaired themselves. The idea was that the powder would effectively increase the speed at which his muscles would grow, but his friend was unaware of the fact that the substance would also decrease the amount of energy (calories) that the body would consume for such processes, and as a result, I would be burning around 1,500 less calories than I normally would a day.
I wanted results fast, so I took around a cup of the stuff and downed it.
I didn't notice anything immediately. I still ate like a bodybuilder and worked out at the gym like a body builder, but my body slowly began to change. I was actually growing larger by the day. At first, I noticed it in my pecs, my biceps, and my thighs, and I grew hard at the sight of myself in the mirror. My large shirts began to get tighter, and I walked with a new sense of confidence.
But then I began to notice the excess weight piling on. At first my abs just slowly became less visible. The ridges were becoming filled with fat. My ass became more rounded, my arms became a little softer. I didn't think much of it, the changes weren't especially noticeable. Of course, the changes began to come faster.
A week into the change, I decided to hook up with a guy I met on Grindr named Miguel. He was also built and sexy, and we met at a bar after work on Friday afternoon. After getting drunk, we ended up at my place, and we had sex. It was more than just physical, and I felt my heart rise in my chest when he smiled. The next morning, we woke up with me spooning him, my dick pressed against his ass, and an unexpected small pot belly resting against his lower back.
He rolled over and kissed me on the lips and told me good morning. He rested his forehead against mine, and we kissed passionately and slowly for some time. His beard scratched against his face, and his hairy torso was pressed against me. Gradually, his hands moved from out from under my arms down to my belly and my dick. He began to grab and pay with both and was kissing me harder and harder, his naked, hairy, powerful body driving me crazy. After a few minutes of this and breathing heavily, I came, and he rolled me over and put his dick inside of me pushing me towards with every well-placed thrust. Finally he came, and I came for a second time from the exertion on my prostate, and we drifted asleep in each other's arms again.
When I woke up a few hours later, the first thing I noticed was his hairy arms wrapped around me and his hand on top my newly-formed belly. His hands were holding mine, but I felt extremely uncomfortable with the weight I was putting on. My pecs had rounded out slightly too and looked softer.
Miguel kissed the back of neck and whispered, "I love your belly. You're so fucking cute." My heart felt like it grew, and my hard-on became pronounced. I should have been shocked and horrified, but I wasn't. I felt perfectly content there in his arms, and I enjoyed the bigger size of my body. So what if I was a little soft, I loved the feeling of his fingers pushing deeper into the flabby layer of my gut, and it turned me on to feel him turned on, his bulge growing thicker at the feel of me, and his fingers playing with the happy trail growing up my stomach. I was usually better about shaving, but I had gotten lazier about manscaping. My new size was enough.
"I think you're sexy too" I told him. He snuggled his body closer to mine.