look up any word, like ratchet:
 
1.
to masturbate; thrusting your hand up and down your shaft as if stabbing your lap, like norman bates would his victim.
I took tila out tonight and she looked so banging that i had to lapstab in the bathroom stall before dinnner was even over.
They caught some priest lapstabbing at toys-r-us again.
by Jared L September 02, 2005