Chubby Avengers One-Shorts 18+

The Experiment(Stony)

*Steve's P.O.V*
Tony wanted me to come down to his lab for something but he didn't say what for yet.When I came down I seen him grinning at me widely and shut the lab door,"I wanted to try something with you Steve,I was wondering if you would let me do one experiment with you?"he said slightly flush.I nodded,"Okay,what is it?"I asked him curious,"It's this new nano armor that I wanted to test out to see if it can manipulate the human DNA from the inside."he said flushing more.I sighed softly at him,"Okay,I'll do it."I said to him,he smiled getting this small metal ball,"You'll have to put it in the back way."he said pointing to my ass.I flushed slightly as I do so and could already feel it melting inside me getting deeper,making me shiver at the feeling,Tony pulled out a remote,"I'm going to try a few places on your body with this,okay?"he said to me as I nodded,"O-okay."I said softly.As soon as pressed on of the buttons I start to get this pressure in my belly,I looked down as I start to see it grow slowly making me flush more,"T-Tony..."I said putting a hand on my belly as I feel it grow bigger and bigger.After a few minutes it's the size of a basketball,then I start feeling pressure in my ass and thighs making my jeans feel a little tight,I moan softly at the feeling with some whimpers,"~F-fuck...Tony...please..It's-it's too much.~"I moaned softly to him as I lean back on a near by counter.Tony looks at me with a dark grin then I start to feel more pressure then before in my belly making me moan more,now my belly looking like I'm nine months pregnant with twins,"~T-Tony...please...it feels like I'm going to burst.~"I begged panting,"Don't worry,you won't I made sure of that."he said to me,I flush slightly as I kept growing.After a while it looked like I swallowed two watermelons and the pressure stopped as I pant and moan,"Turn around for me."Tony said to me,I did as I was told putting my hands on the counter so I don't fall over.I feel him tug at my jeans making me blush darkly,"T-Tony...what are you do~Ah!~"I whimpered softly as he slides his dick into me,I pant softly as he moved in and out of me slowly.I shut my eyes tightly but soon relax and open my eyes again,I looked back at him with half lidded eyes,"~Please..go faster~"I moaned softly as I wasn't thinking straight.Tony nodded going at a quicker and more rough pace,I bite my lip so I'm not too loud,"You like my cock inside your tight ass don't you,Cap?"he said to me.I nodded moaning more loudly as he hits my prostate,"~Y-yes...fuck please don't stop!~"I screamed out moaning.He kept going at the same pace as I kept moaning loudly,soon I felt myself get close and gripped the counter tightly,"~Ha-ah...T-Tony...close...so close!~"I moaned as my voice got tight.Tony rubs my belly gently as he kept going,"Don't worry,I am too,Stevie."he groaned softly,his thrusts get more sloppy,"Cum for me."he said in a husky voice as I let out a choked moan cumming a lot.Soon after he came deep into me making my belly expand more slightly.

*The Next Day*

It took a few hours to get me back to normal,but me and Tony had some fun with his new armour for a little while,even in bed.We talked that maybe next time he should try in out and see how it feels,then we would probably have some more fun.