My friend and his girlfriend were over for a bonfire one summer. She had on really short shorts and a white shirt. She had to go to the bathroom so she went into the house which is kind of a walk away from the fire.
After a while I decided to get something to drink out of the fridge. I was walking out again and noticed she was coming out of the bathroom. I waited for her so we could walk together. As we were walking back I was right behind her and couldn't help looking at her ass. I had a boner and slowly unzipped my jeans and took my dick out. I stroked it and got close enough to touch her with my tip. She didn't seem to notice so I really poked her with it.
It was dark so she couldnt see but I think she knew. She walked slower and I finally exploded onto her black shorts. I rubbed my cum around her ass then put my dick back in. I saw my load on her and was ready to go again.