Boys had already started the game and they didn't notice what happened in fraction of seconds. He asked me to hump on his hard thing. He then asked me to sit on his dick facing my back to him. One bus had already left and the other was waiting for me. My bench was the last one in the girl's row. It had become dark outside and so it was inside. He slowly moved his hands to my front and kept it on my boobs. My girlfriends came to me and said most of the boys are leaving now as they had some other plans after this trip.