A visible protrusion of the stomach caused by something (usually a penis, tentacles, etc.) pushing against the stomach from the inside during vaginal or anal penetration.
If the bulging of the stomach is caused by the stomach filling up with something (usually cum and other fluids), use inflation instead.
The following tags implicate this tag: grabbing_another's_stomach_bulge and grabbing_own_stomach_bulge (learn more).
