look up any word, like bangarang:
 
1.
when someone's penis is bent during an erection. a slang word used to make fun of that said person.
Guy1: Dude that kid flashed me WTF???
Guy2: heh heh he has a checkmark
by Tin Cup 23 March 17, 2010
 
2.
Used as a verb: To make sure something was done right.
"Get over there and checkmark Jake's work, okay? He's new and still messes up like gangbusters."
by Shanya Almafeta April 06, 2004
 
3.
A eupemism for dick (in terms of "giving" or "getting dick")

Can be used as verb or noun.
"Did you checkmark Erica last night?"
"I want a checkmark from that dude over there."
by Jesse February 07, 2003