There are many forums and sites, but the main useful one is
http://www.philippines-addicts.com/forum/
Where are you staying? Prostitution is illegal there but prevalent. In Metro Manila there are two main bar mongering areas: EDSA International Entertainment Complex in Pasay, which is like Manila's Nana Plaza, and P. Burgos Street in Makati. There aren't really agents like HK. There are escort agencies, but that's not the same thing. For straight up traditional mongering you're limited the bars, KTV (which in my experience don't go out), and massage parlours (which are often veggie). Also, leave your WeChat at home, really only hardened working girls will be using it. Most people use Viber or Whatsapp.
But the beauty of Manila is (1) the flexibility and (2) the ease of pipelining. In most places there are clear lines between Pros and non-Pros; in PI it can be a little blurry. My recommendation is to sign up for a couple of dating sites like dateinasia.com (free) and
http://www.filipinocupid.com/ (not free). Create a reasonable profile, set your city to the part of Manilla you're going to and start messaging girls. I generally see about 80% response rate now that I've fine tuned my messages -- don't mention anything sexual up front, just flirt a bit -- flirting with pinays is super easy. Now on the sites about 1/4 are pros looking for their next customer; 1/4 are only looking for good god fearing husband material; and the rest are on the spectrum between these two. That final group is usually the most interesting. You will see a lot of middle class girls with decent jobs there. From there, set time limit (you're only there for a short time), add them on FB (to your fake FB profile) and message their hot friends as well. From there open up google calendar and setup dates. If you play things right, you can have the dates at your hotel -- but not always. Those more on the relationship side of the spectrum might balk at that. Some will insist on bringing a friend as a chaperone -- don't let this deter you. If you win over her friend she encourage her to go back to your hotel. Also, discreetly get her friend's contact details if she's cute as there is a good chance you can fuck her too. The key thing is to experiment. There is such a sea of potential candidates that you should feel any fear trying anything out -- not all of them materialize, in my experience roughly 1 of about every 8 opening message sent turns into a bedding. IF they answer, it's mostly me screening and then flakes that push them out. You will get flakes, either double book some that might flake or take that time to go to the mall and pick up girls there. Yes, going to the mall in Makati, like Glorietta, can be good place to pick up -- just buy girls some things and invite her to try them on back at your hotel. Just don't approach girls randomly... look for those who are looking for you. Also, for you dates, bring little gifts, like chocolate or small stuffed bears -- they will go a long way. Also, unless she's a pure pro, she won't talk about money and would probably prefer you didn't bring it up. After all, she's a good girl and this is a date. Instead just discreetly slip 3000P to 4000P into her bag or hand before she leaves. Also, a little alcohol back the hotel can really help her relax and is a good excuse to invite her back -- just don't overdo it, the goal is to relax not get her drunk.
Have fun!
