Place it at the exact reaction beat after a setup line, not under dialogue. For a bigger bathroom gag, lead in with a classic fart sound button, let this clip answer it, then close with a spongebob fail sting if the character gets caught.
About this sound
A roughly two-second wet, spluttery fart effect that mimics a sudden bout of diarrhea, with bubbling, messy bursts packed into one short blast. It feels deliberately gross and juvenile, built to get a shocked laugh, a grimace, or an instant groan from anyone who hears it unexpectedly in a quiet moment.