I know exactly why she is doing it. But like I say if she achieves it you just have a cum twice appointment.
I honestly would rather the escort did this.
I think I should point out why this was annoying for me. There was no chance of me cumming twice as for it being a challenge yes but, I saw it as a way of ripping me off.
First time was an hour booking with an indie, we had around 20 minutes left, I managed one position mish, for any man who cums before they want this is annoying, plus I wanted to do doggy and maybe cowgirl. It takes me longer than 10 minutes to recover so there was no way I was going to get hard again in the time. Meaning I left early.
Second time was in a parlour with a cum once policy. I managed sex in one position, again. Had around 10 mins left in a 30 minute "session" - so, I filled the remaining time talking to the escort and getting dressed, don't get me wrong I liked talking to her but, I would rather have spent it fucking her.