I would just come straight out and say “please I paid you a lot of money and it would really make me more comfortable if we were both fresh, I would like to run us quick shower now” Just head to the bathroom and start the shower. If she still refuses just say sorry but you smell get your money back and say perhaps another time. With women it is always a gamble as you never know when they might be close to their time of the month or maybe she just came from another client.
Ding ding ding!
I would suggest that rather than blatantly stating "You smell," which would be a mood killer, just state "Look, I wanted to see you because of your stellar reputation and the hygiene that it entails. I appreciate hygiene as much as I'm sure you do."
If she still doesn't get it then say "Sweetheart, I don't want to hurt your feelings, but I'm hinting at something here."
If she still doesn't get it "Look I'm a reviewer on perb, I picked you because of your reviews and the implied hygiene, but I find that you aren't hold up your end of the bargain on that front, so I'm sorry but it's a shower for two or else I think we need to go our separate ways here and I don't feel it's fair for you to keep the rate I paid when we haven't done anything because you aren't living up expected hygiene standards."
With this approach you get to gently imply that she needs to have a shower with out taking her to task (she may actually be unaware). If you just say "you smell" she'll be (a) embarassed and self conscious which will not lead to a great session (b) angry, which will not lead to a great session.
If she's not getting the hint after all that, mentioning the review board will result in her knowing that you know of her excellent rep, have the ability to possibly damage said rep, but are being a nice and fair gent and giving her a chance to either bow-out gracefully by returning you money if she's too embarassed to proceed OR hop in the shower and make the most of it. If she knows you are a reviewer, odds are you'll either get a "I'm so sorry, I was totally unaware" and either your money back OR she'll do what she can to make it a stellar session to entice you to forgive her mistake.
Just my $0.03
**Edit**
PS1 - See Hubba's post below
PS2 - Doesn't every woman do the "dipstick sniff test"? I wish men would do that to their neither regions and back door as well, sometimes it takes more than a single wash to make everything smell squeaky clean.
