I've done 10 times before, but not over a half hour period but rather a full day. That was back in my mid teens. It was a product of finally getting access to high-speed (for the time) internet in the days of dial-up and having the house to myself for an extended period of time. I swear I was quite sore for a few days after it. I definitely wasn't ready for all that online porn at my fingertips....

Nowadays, it tends to be 1 and a half to 2 hours that I need for two times. That's only been with FWBs, I haven't yet came twice with an escort yet. I came close with a particular lady, but in the end I ran out of time with her.