The idea of inflating one’s belly or making oneself appear to be pregnant. So be that with liquid-inflation, unbirth or just strapping a fake-pregnancy-belt to oneself. This, of course, also often plays together with hidden in plain sight, to make something appear different, than what it actually is.
Biology Club by Sumomo-EX
This is probably one of my favourite works by sumomo-ex, as it heavily features carrying some kind of toys or similar for a long time in public with even some latex involved. Biology Club by Sumomo-EX ExHentai