The numerical representation for a ménage à trois between one woman and two men.
Dave: "Hey bud, she looks prettty wasted!"
Ty: "Ya, she does."
Dave: "Shes hot man, go in for the kill, we'll pull some 181."
Ty: "Ménage à trois?"
Dave: "Yeah, but if we pull a clash of swords, I'm out ASAP."
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