Very similar but not to be confused with "the Dirty Sanchez." The Dirty Tebow is when you're doing anal, pull out and instead of drawing a mustache above the girl's lip you draw a streak under each of her eyes. The result looking like she's wearing those dark things Tim Tebow puts on his face on gameday. Writing a message in either streak is optional.
"I thought about trying to get back together with Cathy, but I don't want to touch that since I know Nate gave her a Dirty Tebow."