A sudden burst of air emitted via vaginal area due to excess internal pressure. Usually created via the male penis thrusting in and our of a vagina or other object inserted.

"allow it" means to just leave something alone, or don't worry about it. People in West London say this quite often.

To be honest, I don’t even know.
Apparently this happens during intercourse when air becomes trapped in the vaginal canal, making fart noises.

Simple. A fart that comes out a females vaginia.

Va'gi'nal Fart (noun)
1.Your mama's stinkin' ass after getting a dirty sanchez from a zoo gorilla in heat!
2.The sound pertruding from the vaginal region of the female species or chicken headsas they are known to some
3.The toot sound you here after ramming it home.