I was just in a don't cum challenge with my friend while we were jacking each other off and I told my sister that I was about to cum and she tried killing my boner by saying "just think of your grandma giving birth to a stillborn puppy" and then I cummed it was so embarrassing , I really wished my mom didn't put that video on the television the first time we had sex. It really fucked me in the head, my sister had no idea my grandma actually did it so I can't ask her for my five dollars back.