A Surprising Turn of Events

About a week ago, as I was walking home from school, I was asked by two girls from my geometry class, who came up beside me, to help them with some of the math problems. I reluctantly agreed to stop off at one of the girl's homes and called my Mom from there. However, after we were done going over the problems, the girl sitting on my right on the couch reached over and began to rub my legs and then my crotch through my jeans. I could feel myself getting a hard-on. She unzipped my jeans and pulled them down. Very quickly, things happened that I still wonder about. I don't know why I sat there instead of jumping up and heading to the door. I'm rather shy around girls, and I usually head home after school to play my guitar before supper. But that day, I found myself sitting between the two girls on a couch with my jeans and underwear down around my ankles. She then proceeded to give me my first handjob. Sitting there with her hand working my shaft, I nervously wondered if we would be discovered. Then, when I ejaculated, embarrassed, I jumped up, pulled up my clothes, and said, "I gotta go", as I ran out of the room. I could never have dreamed that this would happen as it did, and I decided that it would never happen again. However, little did I know that I would be subject to almost the same activity just a few days later, and then two or there times a week for several weeks.