belly reduction
When a character's bloated belly is shown shrinking in size through sequence/comic or animation, usually back to its normal state, or, in other cases, to a newly fattened larger size. The opposite of belly expansion.
Belly reduction most commonly seen in vore art, depicting the predator character's belly shrinking as the prey within it is digested. Belly reduction in vore often happens at the same time as the predator character gains weight and/or has certain body parts expand in size (e.g. butt expansion, breast expansion). Belly reduction can also apply to a character's belly shrinking as cum drains out of them after cum inflation.