...criteria.  Some will do it after one visit and some will want to see you several times before they whitelist you.

Some will whitelist you on their own and some may do it if you ask them.  Some whitelist every one they see and some won't whitelist anyone.  The one provider you've seen does whitelist some clients so you can wait or send her an email politely asking her to whitelist you.

A whitelist is not a quid pro quo - you shouldn't offer to write a great review in exchange for a whitelist and the provider shouldn't offer to whitelist you in exchange for a great review (although it does happen).

...when you see a provider you can write a review of the experience. The provider can white list you if she chooses to. She could white list you even if you don't review her. The white list is the TER version of a referral. It says the lady saw you and you were ok for others to see. Only providers can white list a guy. It's ok to ask her for a white list. If I ask I wait until the next day or so not while with her. Don't pressure for it just ask and leave it at that.

Have you read the Self-Help Center. Upper right under the red & white life preserver. Click the link. Read everything in the links you find there.