I know it has been the subject of many a joke and possible because it does happen but this actually happened to my brother,
He was away on a business trip and found himself with some time off so he decided to get a massage in a very respectable Health spa not far from his Hotel, of course the massuse was a pretty but not gorgeous girl as he described her so he asked for the full body massage, anyway during the session he became noticably aroused at which point she said would you like relief,
Now he was taken aback by this as it was a plush establishment but he said what the heck yes please, with that she left the room, now after a while he started to panic as he taught he had done something wrong or failed the test but after what felt like an eternity he said she returned to the room and with a smile she asked him was he finished.
No messing actually happened LOL