When a person quickly covers their computer screen taskbar with their index finger, hiding its contents from someone else. Most commonly used by people who live with their parents and can't stop looking at internet porn.
Duder 1: "Did I tell you that my dad almost caught me last night? I had to do a taskbar cover up to hide my porn from him."

Duder 2: "What? Didn't you look like a jackass with your finger on the screen the whole time?"

Duder 1: "Yeah, he knew what was up. I should have just told him to get out so I could jerk it. He's cool like that."
by westfalia December 21, 2009
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