What is on offer at these legitimate massage places in In Sri Lanka ?
And how many times had it took them to gain your trust ? If they offer some erotic massage it’s very easy to start a conversation to ask them to come to hotel. In other places sometimes we end up risking and termed harrasment.
There are many genuine, reputable spas where it's obvious no extras are on offer. There are others where it's obvious extras can be negotigated - women wearing skimpy costumes, names such as "Body Heaven", a receptionist who hints strongly at it etc. Those are the places to avoid as they're the target of raids. They often disappear suddenly and reappear in new premises under a new name - they're always trying to stay one step ahead of law enforcement.
At the genuine spas, women will refuse to offer extras inside the establishment (but won't take offence to you asking), but if you chat them up they might be willing to meet outside work. My trick was to strip and lie down naked, even if offered "spa pants" to wear, then when the woman covered me with a towel to hide my modesty, you could ask if she can give a different type of massage at your hotel. If no, just accept the nice massage (it's literally £10-15 for 1 hour, nothing to lose).
I met a nice sister duo (no idea if they were real sisters, but they looked very similar), who came together for a "4 hand" massage to my hotel. They took it in turns to film me fucking the other girl, I gave them £60 each for 3 hours and they were over the moon. Got lucky with that one. Others were average, met a smoking hot 22 y/o masseur who agreed to come to my hotel, but was a dead starfish, just lying there and clearly wanting it to be over with. Another one admitted to being a virgin just as I got her naked, I felt bad for her and sent her on her way - it might be some guy's dream to pop her cherry but I felt uncomfortable about it. The best one I had was a 40-something MILF who was filthy in bed, gigantic boobs and literally up for anything. I kept in touch and went back to visit her a year later, she accompanied me touring around Sri Lanka.