Boner in the Boys Locker Room

Back in middle school, we had to take gym class on a regular basis, I think it was twice a week.  We engaged in a wide range of activities and sports.  I was fairly active and enjoyed most of the activities.  At the end of each gym class all the guys rushed into the open shower area to shower, dress, and head to their next classes. One day while in the shower, I heard a commotion in the corner.  One of the guys was standing there facing the wall and a few other guys were laughing.  He quickly turned around with his hands covering his crotch and raced to the door of the shower room to pick up a towel from the stack.  As he passed me I wasn't sure, but it looked like he had an erection (we still called them boners). I was through with my shower, so got out a few seconds later and went back to my locker to get dressed.  Then I heard more laughter.  The same guy was now standing in front of his locker, which was a few lockers away from mine, with a towel wrapped around his waist.  Now I was sure something was going on because the towel was tenting out in front of him.  One of the other guys popped him in the ass with a wet towel and he jumped.  Then another one grabbed his towel and yanked it away.  Now there was no doubt that he had an erection, and his longish but thin dick was sticking out, through wispy blonde pubic hair. He had not yet unlocked the combination lock on his locker, and was having difficulty because he jumped each time he got popped with a towel.  He had to use both hands to unlock his locker, and since he had a top locker with a lock that was at eye level, there was no way for him to cover his dick.  So the scene was 3 guys, who stood naked since they were using their towels as weapons, laughing and popping this other guy, who was naked with an erection that was exposed for all to see. There were also two other guys plus me watching the whole thing.  Each time a wet towel connected with his butt, he clinched his butt cheeks and his cock bobbed up and down.  I also noticed that when they first removed his towel his dick was hard but not quite sticking straight out.  Now I saw his dick was sticking up at an elevated angle.  (I didn't realize it at the time but, although he was embarrassed, he was apparently getting more aroused from the hard pops to his ass.) I had seen many guys naked in the shower, with their dicks shrunken due to the hot water, and in the locker room, but I had never seen another guy naked with an erection.  (I wrote in my story Boys Club that I had seen a friend's erection when he pulled it out and began to play with it, and I even touched and grabbed it, but he still had his clothes on).  I was fascinated by his erect dick and also thought that I would never want to experience the embarrassment of being seen and laughed at with an erection like this.  I didn't want to get caught staring, but kept glancing over as I continued to dress.  Time was passing and even though I wanted to stay and look at the other boy's erect penis (his locker was still not open, so the razzing was still going on), I didn't want to be late for my next class, so quickly finished dressing in my street clothes and left. I (years) later wondered what happened after I left, since he still was quite hard.  Since he was clearly getting more aroused by the wet towels slapping his butt, I would not be surprised if, at that age, he added to his own feeling of embarrassment by ejaculating right there at his locker without ever touching his dick.  I now know that other guys masturbated, jerked off, and did other stuff at that age, but I was a late bloomer and didn't do it until later on.  If he had cum at his locker while I was still there watching, I'm sure curiosity would have led me to start jerking off a lot earlier!