Wash your cups b4 drink…

I went to visit a friend in college. Males could not leave the room unless with a female who lived in the dorm. At three in the morning I had to pee, really bad but everyone was asleep.I peed in a cup, twice. The next day I left in the afternoon only to return to the girls drinking from the cup I peed in. I asked them if they washed the cups and they said that it was alcohol from the night before. I never had the heart to tell them .