if you paid for FS at a spa you really shouldn't tip anything over that (meaning let's say the house fee is 40 and then you agree on fs for 100 with the girl)... at most 20 on top of that if you feel generous, with massage spas, you agree what the tip is going to be after the massage part is over and you are about to get to the sensual part, you tip whatever you agreed on after the service is performed and if you really want to add another 10 or 20 to that after (but really if there is a real reason to)
over tipping is actually a mistake.... never underestimate how quickly niceties become the new STANDARD... let's put it this way... any person on here could afford a 50 dollar loaf of bread, but none of us would buy it.... because IT IS NOT WORTH IT.... value given has to be equal to value received, that's the very basis of economics
you overtip once or twice, the girl actually EXPECTS it in the future as if that's the new standard, then when you think you're giving extra she has a shit attitude because it is NOT extra... to her.... that's just normal now
i'm typically very generous, but i'm very mindful of what is the appropriate thing to do... i'll suppress my generosity IRL too, it's the same reason you don't give kids more candy even if you really want to because you know it would make them happy IN THAT MOMENT... but you know it's detrimental so you don't