Instead of asking "I'd like a 90-minute session tomorrow at 2pm, but please make sure no one else is scheduled immediately before or after me", I word my requests like this:
"I'd like a 90-minute session anytime tomorrow afternoon, between 1pm and 4pm, at whichever time is most convenient for you".
This way, the masseur or escort will naturally choose a time that allows him to cleanup/rest/travel because he knows the entirety of his day, I don't. There might be other doctor appointments, gym time, or day-job activities he needs to attend to besides other clients, and giving him a time range rather than a specific request naturally allows him to choose a time for me that he can be adequately prepared and not rushed.