Over the years, more than once I've gotten a good or better massage that turned into all out sex at the end. HE's that turned into BJs have been most common, but have also had a couple guys jump on and ride me. A couple of times, it was more passionate--a full-body ending turned into making out and then a trip to the nearby bed. One time, the post-massage shower was shared and turned into a second coming, so to speak. Another time a greeting kiss led right to all out sex even before the massage. And once, while I was almost half asleep and still face down, a guy tried to drill me without asking. That got stopped in a hurry.
My impression is that it is very much a function of how horny the masseur is and how he reacts to you personally. If I gave you these guy's names, you wouldn't necessarily get anything more than a good massage and an HE, would be my guess anyway.