greased rat
The particularly great bowel movement that shows no evidence on the toilet paper and no cleaning up whatsoever and makes your day. Slippery and greasy in texture, it does not break half way and comes out in one action.
"You were quick I there!" "Yep, it slipped out like a greased rat"
Grease rat
A bitch with greasy ass hair.
You see bri brodzinski? That bitch was a grease rat!