Knap Butter 

The conglomeration of greasy substance that builds up between the ass cheeks after a particularly long day and resembles the smell of a shart. Occurs most often after it has been greater than 8 hours since a shower and is one of the substances to be removed whilst participating in a hooker shower.

"Girl, I had so much knap butter in my crack last night my thong was greasy!"

Knap Butter by shuddddders October 7, 2009