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A person (usually a man) who succeeds in busting a nut, 100% of the time when he engages in sexual activity. This is a term of high regard, and connotes that one has the sexual prowess to effectively release their load 100% of the time during sexual relations. Also known by the acronym GC'er.
Hey Kristen, I'd love for you to meet my friend, he's a great guy, a real mensch. Like all of the stallions who I call my wingmen, he is a Guaranteed Cummer.

What do you mean a Guaranteed Cummer?

Oh, he cums every time, 100% of the time!
by El Don Parchador January 03, 2011
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