I think a lot of masseurs don't get massages in spas (cuz they are fucking expensive) and so are unaware of the growing list of areas skipped routinely in Spa Massages. A friend took me to Burke Williams regularly when I was young, so when I would do private massages before the escort session, or, grudgingly, stand-alone massages, I was sure to focus on feet, stomach and uncovered butt (maybe ears too), those areas the spas deem too intimate. Particularly the stomach.
To your question, ask. It's super frustrating to spend a massage thinking repeatedly, "is he going to do the _____?"