When a woman has anal sex, there is a chance that she could tear a small hole in her anal wall, over time this hole could widen and allow feces to enter her vagina during deffication. This feces, which comes out the vagina instead of the anus, is know as feashes.

noun (pl. fish)

The true way to say more then one fish. It might not be in the English dictionary but we all know that "fish" can't represent multiple fish.