fish asshole 

when you take a fish from a pond and lick it’s asshole clean

i love eating fish asshole, she said. it’s a great pastime.

fish asshole by ilovefishasshole April 23, 2018

fish's asshole 

The anus of a fish which, given that fish spend all their lives in water, would have to provide a very tight seal. Metaphorically, the term is usually used in conjunction with the words "tighter than a" to indicate that someone could hardly be more frugal with his spending.

Tom: "I never leave a tip when I eat out- even if the service was excellent".

Jerry: "Man, you are tighter than a fish's asshole".

fish's asshole by poo hole December 21, 2012