How do you define "things that are unique to bangkok alone"? Or sleazy / chaotic" environment?
For the first question, i assume you are in Singapore and your experience is limited to FL Dome 1 and Dome 2 type of experience, and maybe to Singapore's Thai Disco?
If you really want to experience the uniqueness of Thailand and Thai ladies, i suggest the following 10 activities (not in order of priority):
1. Go to Thai Night Club and enjoy the atmosphere and Thai Songs. Always better to go with other bros and try your luck in picking up ladies there.
2. Go to The Pimp or any G-Club and experience it at least once. Be prepared to spend more if going alone.
3. Go to Agogo bar at Nana or Soi Cowboy. If Bacarra is open, go in and enjoy the glass ceiling view.
4. Go to a soapy MP and experience the bath tub service. Unfortunately most of the big soapy MPs not open yet, but you can still experience this at the smaller MPs along sukhkumvit.
5. Go try nuru service at one of the jap joints along sukhkumvit.
6. Try one of the BJ bars .
7. Try a kapoo joint.
8. Get a Pretty MC model for ST or LT. Bring the escort to a nice restaurant and be the envy of other guys - bro tonybkk or Apple can help arrange.
9. Go Thermae and get a girl for ST or LT. Can always go sit there and drink while ogling the large selection of ladies.
10. Try a session with a LB once. If you not so adventurous, then can go visit cabaret show instead. I think still have such places in bkk, but not sure.
Whether you end up with lady (or 2 ladies) for the night is up to you. No one will judge if you end up with LB that looks like Nong Ploy
Chok dee na (Good luck!)