Is it legal or illegal to pay someone:
-to give you a basic massage while both of you are naked
-to give you a nude strip show
-to makeout (kiss with tongue) with you
-to give you a hand job
-to give you a nude lap dance
-to play with her naked boobs
-to undress and show you her nude body while you masturbate
-to kiss her naked butt
-to take a piss on you

The exact answer to all of those questions is that it depends on what jurisdiction (state, county, city, etc.) you are in at the time.

4 (hand job) and 6 (play with her naked boobs) would be illegal in the vast majority of jurisdictions in this country.

What if the only contact is between you and her strap-on? It's not really part of her anatomy, so where is the fine print on that?

When in doubt, assume illegal.  Some of the above (kissing) is probably alright but use your best judgement.

Check out well reviewed ladies and the question is not that important.