Cumming by flexing muscles

lmao funny story that's how I first cummed as a kid. It was scary at the time, but I thought that was the only way to do it

Yup! I remember the first time I orgasmed, I was doing pull-ups at school and felt a weird tingly feeling that felt really good, so I kept doing it. For several years I would only "masturbate" if you would call it that by contracting my abs really hard for a few minutes.