My family and I had gone to visit some of my dad's friends in New York. We had gone to NYC for the day and we were on our way back to the motel. We were in a seven-seat Ford Explorer and I had the back two seats all to myself.
I had gotten an erection and was feeling horny. I started to rub myself through my shorts. Seeing a blanket that I had used to cover up during the ride to NYC, I covered myself up with it. I carefully and quietly undid my shorts and let my erection come out from over the waistband of my boxer briefs.
As we drove through NYC at 9pm that night, I slowly started to stroke myself, trying to be as quiet as I could. My strokes became quicker and quicker and I tried to quiet my shallow breathing. After about ten minutes, I could feel myself getting ready to cum. With my free hand, I grabbed the blanket tightly as I tensed up and came all over the inside of the blanket. I tossed the blanket aside, re-buttoned my shorts, and slept for the remainder of the ride back to the hotel.