stomach stuff:

full gut with an erection. the movements inside the stomach stimulate the erection pressed up against it

being stuffed full of something (especially cum) and then having a plug put in, so you have to spend the rest of the day full and sloshing

or having a plug in with any sort of full guts

cashier jobs, rumbling gut hidden beneath the counter, just barely holding yourself together

grinding against someone else’s stuffed gut (but not allowed to cum without permission)

on all fours with a huge gut hanging below

gut so big it presses into your thighs

internal shots where you can see a stomach swelled tight and at its limit (as in, no space left around what’s in it)

gurgles and movement from the lowest part of the gut, below the belly button

an egg-layer holding in their eggs, making their gut expand

impending diarrhea. the heaviness, the sloshing, the churning, the sensations and noises

someone with a terribly upset gut in need of a bathroom, but they hold it in just for you

someone on all fours, laying on a gut so big that their legs are lifted off the ground, pressing into the bottom of their stomach

slimes in tummies… heavy, sloshy, liquidy with a mind of its own, moving around in your guts

sex with a stuffed belly, the movement and shaking causing trouble

pleasuring yourself inside someone else’s stomach (especially if your cum upsets their stomach further)

laying face-to-face against someone with a noisy stomach, and you can feel every movement and gurgle where it’s pressed against your own gut

audible rumbles and bubbles building up right before a burp

(bonus if they hold it in, causing their stomach to growl even more angrily)

not pulling out after cumming; instead, keeping you plugged up and sloshing full of cum

not stomach specific:

visible bladder bulge

balls sloshing and swollen from being denied orgasm several times

having a very large and thick tail, and grinding on it