He smiled and waved and we went along for several miles flirting back and forth. My sister in law resumed her position on my lap and I slid my cock into her pussy. We passionately kissed and as out tongue wrapped around each other, I unzipped his fly. Then she sat down, letting my member slide all the way inside her, lifting herself up and then letting her self down again, over and over on my cock. I willingly agreed and after five minutes we both climaxed at the same time, my hot come trickled down her leg.
I don't know how I did it but I told her I was about to cum. He grabbed my hips and plunged deep into me. I don't think I've ever ejaculated so much semen and with such force in my entire life.