I think age is one major factor.
When young, didnt' last as long...8-10 mins per pop, then only need 5-10 mins to recover.
Nowadays, I last 15-20 mins, I don't know if this from age or slowly being more desensitized as i get older. I also need a minimum of 20 mins to recover.
With that math, my max is two times a hour.
***Sauna girl told me her a client she had...7X in one 2hour session***
how embarrassing