Masturbating in front of three girls

During the mid-70s, I went to a strict fundamentalist college. The sexual revolution was in full swing everywhere, except at my school. My freshman year I was still dating my high-school girlfriend, although we were going to different colleges in neighboring states. The university my girlfriend was going to was a few hours away from me. It was a very liberal school in that members of the opposite sex were allowed to stay overnight in the dorms. My girlfriends dorm room was set up with four rooms of two girls each, sharing a lounge and two bathrooms. Often one or more of the eight girls would go home so when I would visit for the weekend, my girlfriend and I had a room to ourselves. The other girls got comfortable with me hanging around and because my state had a lower drinking age, I often bought liquor. During one of my visits, my girlfriend and two other girls were in the lounge on a Saturday Afternoon drinking. One girl was taking a sex-education class. We all were looking at the textbook. Even though the book just had drawings, they were very explicit. Our fundamentalist college would never teach a class like this. Looking at the book, one of the girls asked me if I was normal. I told her yes. She then said that I must masturbate because the book mentions that a huge percentage of men masturbate compared to a lesser percentage for women. I told her I did and that according to the book, some of them must also masturbate. I went for broke and told the three girls that if they show me how they do it, Ill show them how I do it. My girlfriend did not object to my conversation so I took this as a green light. The girls were hesitant so I told them that all they needed to do was to take off their clothes and they could watch me. There was still hesitation. The shy girl then asked, What if we only took off our tops. I told them that if they let me touch their breasts, I would take off all my clothes and masturbate in front of them. The shy girl was holding out but my girlfriend and the other were talking her into it. I felt they needed some encouragement so I took off my pants and told them that if they took off their tops I would remove my underwear. I stood in front of the girls in my underwear and shirt. My girlfriend and one girl took off their tops, but not their bras. I removed my underwear and the rest of my clothes. My girlfriend and one girl then took off their bras. I told them I would not start to masturbate until all of them were topless. The three of us told the shy girl that because this was her idea, she needed to become topless. She took off her top and bra and I started to masturbate. I felt my girlfriends breast and then the other girls. The shy girl did not object when I also felt her breasts. I told them they could also touch me and each of the girls also felt my cock and balls. When I came, I was lying on my back with all three girls putting their hands on my body, me jerking off with one hand, and felling the girls breasts with my other hand.