To literately go Crazy on a woman, using multiple positions and ejaculating multiple times, the term kill is for when you are done and have no stamina or dexterity left in you thus killed and crazy cause well its crazy.
comes from the Latin root killcrazi or to have sex constantly
Sam: dude i went fucking Killcrazy on my bitch last night!
Bob: Shut up you Jive Turkey
Sam: i'm serious i was shooting blanks by the end