The action of stabbing someone with a knife, then repeatedly penetrating the open wound with one's penis. Usually resulting in ejaculation by only one of the parties involved.
Similar to a butt hole (aka: anus) a butt slit is what occurs when a man has had so much anal sex, or many big objects in their anal cavity, that the anus is no longer a hole, but instead becomes a slit.
I hate when guys on Grindr send me pictures of their butt slits.
(noun) the rectum, the opening of the anus, poop-shoot, or asshole. Often referring to the receiving orifice during anal sex. Also known as a muscle-cunt in gay anal sex. This term is usually associated with a shitty-kitty or a dirty deal. But Feces need not always be present unless you are referring to a shitty slit, wherein shit is an adjective.