Dawn - Dawn's Experiment
The slight swelling dawn had noticed many times before wasn't just lust, or backed up sperm, it was her actually growing, defiantly fighting against the force that held her release in check.
Stratagem
The bulge had reached to near the end of his shaft and his fat cockhead when the flow of backed up jizz broke past the obstruction and erupted with its full fury.
Twice The Satisfaction
Now, cosmo was no longer envisioning a belly swelling with backed-up cum through the paper pages he held in his hand in a library, nor was he watching that glorious curve extend proudly forth through the glass of his television screen; he was the one succumbing
Goku's After Life (Act 2)
He went cross-eyed and out rushed ten years worth of backed up cum. he fired cum everywhere! "guahhhh!!! make it stop!!! make it stop!!!" a demon shouted. one brave demon gripped hold of goku by the cock and balls and jammed a metal rod down his cock.
A new hive
Neither of them had any place to go, so her clogged prostate continued to swell with backed up cum and eggs, her belly starting to bulge as it expanded far past any reasonable size.
[COMM] Tossing Apples
Beneath the ring his prick was thicker than normal, bulged out with the pressure of all that backed up sperm inside it. another two vibrators were pushed in, pressing against the sides of his cock and his slit and making him squirm in delight.
Its Lonely in Space (all chapters + epilogue)
Jared's balls had grown in size as they had filled up with his backed up cum. jared crawled along the ground his knees bleeding from crawling too long. tears streaming down jared's face as his body and mind were filled with horrid conflict and need.
Syn’s Glory - Second Draft
"for an asshole, you sure know how to fuck a bitch." the bear finally said as syn pulled out to allow his backed up cum to flow out of her pussy to join the splotches of cum on the floor already there.