to encourage them to write reviews, go down this line of questioning (if at any point he seems dismissive or uncomfortable talking about such things, change the subject and don't pursue further):
(...at the end of the session...)
You: ...so where did you find me, if you don't mind me asking? I'm always curious.
Him: Oh I think I first saw you on blahblahblah, or maybe on yadayadayada. I really loved your thingamajig!!
You: Oh thank you! I'm curious, do you ever read reviews when you're researching ladies?
Him: Yes, I read them but I usually don't write any. I just like to get a sense that a lady is legit, etc.
You: Well as you might know, I'm fairly new, so I am grateful to have a few that you could look at. Getting reviews really helps a lady establishing her legitimacy early on, so I love receiving them!
Him: Oh, maybe I could help you out by writing one? I've never done so before, but I'd be happy to do it to help you out!
[OR]
You: ...so where did you find me, if you don't mind me asking? I'm always curious.
Him: Oh I think I first saw you on blahblahblah, or maybe on yadayadayada. I really loved your thingamajig!!
You: Oh thank you! I'm curious, do you ever read reviews when you're researching ladies?
Him: Nah, I'm not into those sites. I'm in this for the ladies and the fun experiences; I don't have time for all that.
You: Oh right~ I'm sure your job and home life and travel must keep you SUPER busy! ~change the subject~
You can also simply put notes in your ads and on your website that state that you would love to receive more reviews. Gentlemen who are at all inclined to review who want to do something nice for you will see those notes and go out of their way to do so.
I don't recommend offering a discount for reviews. It's not against the rules, but it will draw bargain-hunter types to review you. They will write you different types of reviews than your ideal client base will. Always market yourself to your ideal client base, and don't forget that your reviews are a part of your marketing. So unless you think bargain hunters are your ideal clients, don't fill your review profile with reviews written by bargain hunters by offering a review special.
If anything, offer $50 or $100 discount off a FUTURE visit to TER members who write you a review. That way, the discount isn't the incentive for them to see you the first time, but just a reward for writing a review after the fact, if they want to repeat with you. Now you're encouraging repeat visits amongst your target client base instead of encouraging bargain hunters to see you who might not see you otherwise.
Just my two cents. Good luck!! 
