when you're wearing shorts that are WAY too short and people can see your cock head when you sit down.
In the episode of Friends "The One Where Monica and Richard are Just Friends" when Chandler accidentally sees Robert's business hanging out of his shorts and gets up and says to Ross "The man is showing brain".
by Chandler Bing's Friend May 29, 2006
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(v) - when one's scrotal sack is visible, regardless of clothing. Usually the result of short shorts. Can be related to elephant sack.
Look at that guy's shorts! They're so short he's showing brain!
by Jim September 1, 2003
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When a man or boy wears pants that show details of their genitalia (lines of penis head, testicles, etc.)

or

When a man or boy wears shorts that allow their scrotum or penis to fall out and be visible.
Tim walks into the gym after a run in his short-shorts, and as he is talking to his friend Bob, his sack lolls to his side. His shorts are so short everyone can see how the anabolic steroids have shrunken his testicles and penis.

Bob: Dude, get some longer shorts, you're Showing Brain to everyone.
by Real Men Don't Sparkle September 27, 2010
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