Yerk
v. (to yerk) the act of stroking your dick for brief pleasure, and putting it away before ejaculation in order to carry on with your daily activities without dealing with the post-jerking off laziness/cleanup session.
Yerking often occurs during late night homework sessions when one becomes fed up with his work (writing an essay, doing research on the computer, etc.) so he decides he wants to jerk off... but doesn't want to deal with the jizz of it, and simply looks up "tits" on google images as opposed to watching full-out porn. Yerking often leads to jerking off anyway.

Henry - Yo Pat, what'd you give up for lent?
Pat - Masturbation... I know... what the fuck was I thinking??
Henry - Well at least you can still yerk.