noun: the slow pressing of human feces between one's fingers while performing the act of fisting one's anus
After a long night of heavy drinking (or not) as you fist a girl in the anus, your hand cramps open to the point where a smooth extraction is impossible forcing the girl to attempt to push your hand out as if she were pooping. During this painful attempt to free your hand, you begin to feel a sensation between your fingers similar to that of hot smooshed-up bananas, being, of course the seepage of her feces.
"Last night I was up in this girl's shit, literally man. I got it stuck up in some mad seepage."