Cumming without stroking?

Last night I managed to cum twice without stroking my cock. It took about an hour each time and the cumshot was massive but I’m wondering if this is a common thingP.S it involved rubbing my cock between my thigh and my underwear Get your own Orgasm Control toys: For men: http://www.amzn.to/1V6XQvv For women: https://ift.tt/1UWn54n