The act of starting the sexual act of "doggy-style" proceeded by knocking both hands out from underneath the girl forcing her to drop her head in the sheets/pillow/cement; forcing her to arch her back much like a kitten. The "thump" is derived from the sexual act of a donkey punch. A donkey punch involves knocking the female unconscious by hitting the back of her head forcing her butthole to tighten. Urban legend says after many generations, the "punch" became a "thump."
Kyle kitty-thumped the shit out of Reagan last night.
Austen was being a douche so we kitty thumped his ass.
That girl is so hot but is a bitch...let's kitty thump her.