So what's in a massage?

Serious question. I've never hired but recently searched. Noticed many guys who advertise as escorts as well and seen some who no longer advertise as escorts but once did. Are these performed in the nude? Do most of them upsell to escort services? Is it cool to ask them before one books an appointment? This guy here is of particular interest. https://www.masseurfinder.com/mobile/listings/view/hawaiianmassage/
He doesn't strike me as one that engages in anything other than an...

So what's in a massage?