Another unique way to spot a katoey
A friend who has lived in Thailand a long time told me another way to tell if she is an it or he. Ask if she would like to go back to the room and play dummy. Dummy is a card game all the girls love. Guys never play it. If she doesn't know what you are talking about, check for balls!
We were in the club at the top of NEP that has the glass floor, so you can see the girls above who wear no undies. A good looking girl was sitting with him and to prove the point, he asked her about going back to play dummy. She did not know what it was, so he went for her crotch. She said, oh that was removed! It may sound crazy, but it works.