I'm not sure whether to share this or not but here goes anyway - when I was a shiny-faced new massage therapist, a client came for a treatment. He preferred to be massaged naked and with no towels. I was a bit about this but thought, hey, I'm a big girl now and a professional, I can deal with this, if anything dodgy happens I'll just slap his chap with the towel as suggested by our tutors, or leave the room until he has calmed down again.
So, I was massaging his thigh, keeping a weather eye open for any dubious erectile movement (none) when he bloody well ejaculated! Soooo wrong.
I said "oh, does that often happen" and he said "yes, sometimes" - he seemed thoroughly unembarrassed by it, so I just wiped his leg with couch roll (eww, I know) and carried on with his massage.
I canvassed opinion (male friends and colleagues) as to what this meant and concluded that it was NOT sexual, just a strange physiological reaction - my massage tutor told me that he had a client who had this reaction to massage as well, regardless of whether the massage therapist was male or female.
But I still sacked him as a client, on the grounds that if he knew this was likely to happen, he should have kept his underpants on. Rude not to.
BTW: the massage I do is not particularly sensuous, it's generally deep tissue therapeutic.