Sharing my experience of the Whitechapel branch. Met a girl called Rose, probably mid 30's and quite large. Paid for hour long Thai massage. Have to say the massage itself was a fantastic massage - would easily have paid £80+ for the massage alone , rather than the £50 that it cost. Wasn't sure what the crack was so had my pants on from the start. After about 35-40 mins she yanks my pants half way down and starts massaging my ass, then she asked if it was easier to take pants off which I did. Started massaging my balls then turned my over. She wanted £100 for B2B. I just asked for HE but she was quite insistent not giving me a price for that. She asked how much in my wallet., I said £50 so she said it was my lucky day and she would take 50 and an enjoyable HE. Guessing for these prices you are not going to get a slime 20 something so assuming that this is the standard type of Thai person you would get?
As someone not used to this type of massage, do you normally ask about extras up front or do you wait till they turn you over? Now I know they do that sort of thing there I am assuming you negotiate everything upfront?
Negotiations are down to how charming you are, how comfortable you are being brazen about it and how you prefer the session to go.
If you're shamelessly after a cheap max mileage sex service then ask before you even get undressed, using as much (or little) charm a la Han Solo as you like. Always say you've been before, if she asks more about those visits then it's an open invitation to negotiate.
If you like to play the game and see if a you can get a happy chirpy girl to be frisky with you then undress completely, do your best flirty, jokey self and react to her touch in an encouraging fashion.
Price-wise, unless the place is particularly ropey and tatty looking then open at 40 for b2b and don't part with more than 60, being sure that you get fully naked, both on the table action. Some will try to get away with only topless and standing beside the bed rubbing their boobs around for a bit. If they insist on too much then just say not to bother and either exit to get your money back if before session or take the hit for the massage. IF she's particularly crap and delivering for the rest of the session because she's got the hump then you could ask for management and either get a refund or a replacement. This of course is only if you're up for some frustrating confrontation to minimise your losses.
Generally avoid accepting any girl asking way more than you're offering suddenly discounting her service because you will be the one getting the shaft.
There are many girls who are up for delivering a decent/exceptional service at the +40-60 mark so don't keep parting with more because you'd be better off seeing a "proper" escort or brothel worker for the same or less.