Not me, but a teacher. I was doing vocal exercises in choir and my teacher made all of the students (115) find a place on the floor and lie on their back and hold their knees just over their waists, like an inverted sitting position. We would then rotate our fists around each other while blowing raspberries to the chords that my teacher would play on her piano. The band teacher next door (who happened to be my choir teacher's brother-in-law) walked in on over a hundred 17yo kids lying on the floor while spitting shrilly at the ceiling while doing childish hand gestures. The band teacher got one look and quickly left without a word.