3 Way By Mass
When you're having sex with a girl, who weighs as much as two girls. You're sexual experience weighs in as a 3 way...but there are only two people in the bed.
Person A: "Is John really hitting on that fat chick over there?"
Person B: "He'll be in a 3 Way By Mass soon enough."
Person B: "He'll be in a 3 Way By Mass soon enough."