I learned self control the hard way more than half a century ago. It was the spring of 1970 and I was a sophomore in college. I was in a student lounge with six or seven other students, about half women. One of the women I will call Robin for this story. I knew her slightly, having talked with her at lunch in a university dining hall a few times. She was a brunette, athletic, and about 5'10", which is two inches taller than me.
The lounge had several pinball machines and we were all watching a woman I will call Christine playing pinball. I was sitting on a couch next to Robin who was sitting on one of her legs with her bare sole right next to me upturned on the couch.
I had little self control. I stroked her bare sole with my right index finger.
Robin laughed out loud, turned to me, and slapped me across the face. The slap was hard enough to leave a large red mark on my cheek and loud enough to distract everybody's attention from Christine's wriggling rump as she continued playing pinball.
"I don't like to be tickled," was all that Robin said to me before she turned away from me, got her leg out from under herself, and put her flip-flops back on.