I think you should read this article. http://www.bbc.com/travel/story/202...thai-massage?referer=https://www.bbc.com/news As per norm, it was the Yanks who changed the perception by demanding more!!
The article is about Traditional Thai Massage, not the type of massage your mates, obviously, went for.
Sorry mate I didn’t mean “oily” was another name for “traditional” I meant for the other type of massage