A Gilseth is when you pop a boner so hard that you can't get it to go back down. after a while the Gilseth get so hard it cuts off circulation to your balls turning them blue. You generally get these when you see a really hot chick or in some cases a guy if your gay or a transvestite.
Dude check her out!!

Dude i know i have been popping a Gilseth for last ten minuetes. (in a whisper) It hurts so bad.
by boner6669 March 23, 2012
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