I learned the hard way that night.
I was only 15 and I was seeing this boy who was 18. He had a small pick up truck and we were out in it that evening. We ended up outside the city limits parked off the road to make out. Things really got to cooking and that was when Jimmy took my arm and put my hand in his lap. He was setting me up so I could feel his dick. When I felt it, it was rock hard. Jimmy put his hand on top of mine making me squeeze it and he said 'See what you do to me'.
I felt excited that I could make him get like that. I continued to squeeze it even after he moved his hand away. It felt so big. Jimmy then asked 'Want to see it'? I told him 'OK'. Jimmy opened his pants and pulled them down. He then sat back and pulled his shirt up. His dick was standing straight up. Jimmy said 'Go ahead and touch it'. I did and it felt hard and very smooth. Jimmy then said 'Here; do this' taking my hand and moving it up and down on his dick. He then said 'This will make me cum for you'.
I continued to do this and it wasn't too long when Jimmy went to thrusting his hips some and making hard breathing sounds. He then let out a loud groan and stuff started spurting out of his dick. I turned it loose and jumped back. His dick jerked around still spurting the thick white stuff. It went all over and what a mess it made. It ended up on Jimmy's door, his belly, the steering wheel and on the seat between us. I sure had no idea it was like this when a boy came.
Well, after this first time, I then knew what to expect and do. I'd hang onto it while he came and would hold a hand full of tissue paper to catch it. Soon afterwards, Jimmy got to where he wanted to do that in me (my pussy) so I stopped going out with him. He finally got an older girlfriend and it wasn't long after that that she ended pregnant. Sure could had happened to me if I'd kept going out with him. It was fun watching him spurt that stuff out but I sure didn't want it inside me. Of course, I've long since changed my mind about this.