You don't want it to take ages to count especially for a half hour booking. But better to give her a tenner in £2 coins than expect change. And no, if it is done politely and with confidence of course you don't 'come across as a twat.'
Some people here are still too bothered what the prostitute "thinks" of them, and maybe read Saafe too much. Half the time she doesn't think. Other times if she does think, she's a business woman. She's not interested in your romantic fantasies of delicately placing your crisp clean notes in a vellum envelope on the mantlepiece. She wants to get the 'paperwork' out of the way, the same as any sensible punter does, even when the 'paperwork' includes a few coins!
I did have a slight smile when a prossie -- who gave very good service I would add -- asked me not to bring £50 notes again if possible. I asked her why, and she replied, "Girls like me don't go into the supermarket with £50 notes." Fair enough. She knows her place and takes a pride in her work. (As opposed to a stuck-up slag that wouldn't take a £2 coin into a supermarket??? Give me a break!!) If I pay for a role-play, the time starts after I hand over the dosh, thank you very much! Not during...