Actually, when guys discuss "friendly", it means whether there's going to be a surcharge. Two places I can rec, there's no "guest fee". One is JW Marriott, Soi 2 (probably because of all those horny CIA, US Army, State Dept. guys who have rooms there
), the other is Davis Hotel on Soi 26, but it's on the Rama IV side of 26. Same as in former Davis Entertainment Group grand poohbah P. Chuwit (forget his last name but he's cult hero in BKK), you know, the aging stuffed lion who just got CIM icon? Yeah, that one.
I can't rec the JWM anymore, the staff has gotten too arrogant, the place is in somewhat of a decline due to lack of money spent on maintenance, but the Davis my local Thai friends give the thumbs up to. Davis isn't cheap either, but it's an embarrassment what JWM charges and what you get-questionable plumbing and AC at times.
But...default at most hotels is to charge for a guest. As the truly 5* places, Regent, Mandarin, etc...guests are strictly prohibited. But...girls are available, you just have to know who to ask.