I'm re-posting this due to unprecedented demand.
So many times I read about offs not living up to expectations. Here is a simple plan to ensure success.
1) Tell the boy what you are hoping for before you off him. Make it clear what you want.
2) If he says he doesn't............then don't pressure him either in the bar or the room.
3) Tell him how much you will tip him.
4) Unless you've stipulated he must come (see 1) then don't demand it and don't insult him if he doesn't. (I know for a fact many do.)
5) Do invite him to have a drink from the mini bar. He is your guest. (My rule is NO alcohol, not even beer if they're on a motorbike.)
6) Pay him nicely. Thank him for his time and assuming you've enjoyed your time with him tell him.
7) Give him a nice kiss goodbye, even if you drop him of right outside his bar. Gay or straight assuming you've followed the above rules he won't mind a bit.
8) Next time you go into the bar, if you don't off him again then give him 20/40 baht. It's nothing to you and shows you thought he was a good off. It also buys him dinner.