When I was thirteen, I took a pair of my mom’s panties and used them to rub on my dick while I jacked off.
One night, I put them on and while laying on my stomach, I pretended I was on top of a girl fucking her. A pillow was under my chest and I humped the mattress, making sure I didn’t cum in the panties.
About two minutes into humping, my mom came in to ask me about my lunch for school the next day. I was mortified. There I am, sitting up in the bed with her panties on and with a hard on inside them. Mom stood there for about fifteen seconds, walked over to the side of the bed, and sat down. Without saying anything, she started rubbing my dick on the outside on the panties. She got faster and faster until I shot my load all over myself inside the panties, which then soaked through to the outside.
Mom stood up and told me to put them in the hamper to be washed and walked out.
The next day when I came home from school, my clean clothes were on the bed, folded and on top of my underwear were three pairs of my mom’s panties.
She never said a word to this day, but I jacked off and shot cum in those panties for a long time, always putting them in the hamper and having clean ones to cum in or on whenever I needed them.