The rule that either a friend is A) with his girlfriend or B) doing something with his family. In either case he is too busy to hang out with friends. Betting usually occurs among the collective group whether he cannot chill due to A or B.
Friend one: "hey, we were supposed to hang out yesterday, what happened?"

Friend two: "oh, I was going to but then my mom told me I had to go shopping with her'

Friend one: "great, we didn't hang out and I lost $20 thinking you were with your girlfriend. God damn Kenny Principle."
by Lingua_Franca May 22, 2011
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