My approach. Not for everyone
I see there's some convo on how to approach the AMPs. I used to be a HE guy then slowly moved to BJs and eventually FS. What can I say, my grime has evolved over the years. I know this isn't a popular opinion, but I like WaWa. They've treated me well. I used to mess with "Candy" over there for like 2 years. I'd come in once a month and see her. I always call ahead. I haven't seen her lately, but if I do, I'll report back.
Even if she wasn't there, the mamasan would have me swing by and when I did, I'd make sure she knew I was the one that called. Since she knew me as a fairly consistent repeat visitor, even the new girls treated me well. (If I run into "Pepsi" again, why'all will definitely want a report on her).
On to my approach. It's simple. I pay the house fee and then leave the tip on the shelf in plain site. $. 8 (for Candy I'd do $$, but her massage is worth it). If they ask me what I want to do, I just say, "whatever you'd like. " It has always ended where I want it. If it ever doesn't, I plan on just letting the mamasan know on the way out and making damn sure she knows if it happens again I'll take my business elsewhere. If they ask for more, I just tell them, "I've been coming here for years and this is what I pay. If you don't like it we can call it. " I'm not going to hate on them trying to get more, but I know what to pay.
You may think it's not worth the risk of not getting what you negotiate, or that I'm paying too much, but luckily, I don't really care. It's worked for me for like 3 years. I'll probably swing back by there this week. If I do, I'll finally be able to provide a report.