A Little Too Much Rubbing

Back in high school our band room had a big instrument storage room that some of us would hide in. One morning my girlfriend and I were skipping first period in there because I was leaving for a two day field trip later that morning. We were in the instrument room making out. We had been making out for a while laying down in one of the giant cubby holes and had wound up spooning with me behind her with my hard cock pressed between her butt cheeks (all of our clothes still on) and reaching around to rub her crotch and feel her tits under her shirt and bra. I was humping her butt this way and it felt too good and before I knew it I went too far. I pressed my cock hard against her butt and began pulsing wads of cum into my underwear and jeans while I squeezed her tit. When I finished she giggled and asked if I had an accident. I had to leave shortly after and only had a few minutes in the bathroom to try and wipe up as much cum as possible, but my underwear was still wet and cold for hours on the bus out of town.