Kill my ass

(1 An exclamation commonly used to convey extreme annoyance and/or frustration at ones current situation

(2 A term used during anal sex to convey wanting to be fucked up the ass harder, presumably until the participant's ass is in pain or "destroyed"

In the first context, the term is not meant to be taken literally or to show actual sexual attraction.

In general, the term kill my ass seems to have originated from the similar terms fuck me and fuckmeuptheass.