My standard answer with an hour bookings is, "You have me for an hour, that's between you & your god."
No one has EVER popped more than twice & interestingly enough, I'd say 90% of them do NOT go for that 2nd pop. I've finally concluded they simply want to know the option is there. Fuck if I know.
30 minute sessions, you get 1 pop, what are you, Superman? GTFO with that shit. You want more than one cum, you're going to pay for more time, the end. That IS just what I tell them if they get fussy, they either agree or hang up *shrug*.