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A small brown stone (rock) that comes out of your penis during sex with people of the same sex, sometimes comes out in text message format or coated in pepto-bismol
"Ahhh what was that"
"oh nothing just a cock stone"

"Whats that pink boulder?"
"think its a cock stone with pepto-bismol on it, just ignore it"
by Olly Webb June 27, 2007
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