generally they will give you a little cue such as:  "Is there anything else I can do for you?"  or some similar type come on.

That's your cue to ask what services they may offer, but be polite and low key the whole time.

You can also offer some cues yourself such as:  "You sure are very pretty." or, "I'm getting excited looking at you."

If they are willing to offer more, they'll let you know.  You can then start the bidding.  They will either nod or shake their heads instead of answering, for obvious reasons.

If the place is strictly a happy finish kind of place, a tip of 20-25% of the base fee is fine if you feel you got a decent massage and genial service.

If she massages your ass when you're on your stomach, she's going to give you a happy ending.  If she stops at the waist and starts again at mid-thigh, hang it up!

In every case it was pretty obvious the moment I got there. They are scantily clad, take you by the hand into the room, and immediately help to undress you. I don't think there is any doubt. If when you call and they offer a table shower then I would think that pretty much settles it.

Last thing: be sure to tip them well.

Welcome to the wonderful world of the asian jack shack. When at a new place, i just play it cool and let them control the atmoshere. If they are offering more, they will let you know.  How much more is the question usually. A word of advice though. If you stumble into a place that doesn't offer more, don't push the issue. The ones that are true massage seem to take offense to the suggestion of something more. Of coarse a line I like to use that is a dead givaway is, can I give you a massage?
As for pricing, I hold to this standard: hand release with clothes on $40, Hand release with clothes off $60, Hand release with oral $80, and full service $100. This is of coarse on top of the room fee paid to the owner when you arrive.