Gaps house runs off Ratchadamnoen street, and is in the LP....not far from Thapae Gate.
If you did end up doing it in BKK though, after practising on people and being practised on all day, you get home so mellow, relaxed and knackered, Bangkok doesn't feel full on anymore!!!
Chiang Mai is a great place to spend a bit of time in
10

joyasia
Pro tip