The "trish cup" is the center-most cup in a rack of 10 beerpong cups. Since the center cup is the easiest to hit, Trish, was the name given to this cup, because Trish is the easiest to hit.
My friends and me were playing beerpong. I threw the beerpong ball at my opponent's beerpong rack. The beerpong ball I threw landed in the center most cup of the rack of my opponents. Thus, I yell, "TRISH CUP (in a tone that starts in a lower tone and then rises two octaves)."
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