I've seen a few posts where it's been suggested to not socialise with filipino males. In my opinion, this is at best over cautious and at worst, bordering on xenophobic!

Obviously, you need to use your common sense. If a filipino comes up to you in the street and invites you to play cards or wants to exchange some money, don't go anywhere near them!

However, if you meet some locals as you go about your daily business and become friends, it can be a great "way in" and you'll experience the city in much more depth than you ever could as a tourist. You just need to find people that you "click" with, who maybe have some similar interests to you or are from the same socio-economic group (likely to be the more wealthy filipinos).

When I spent a year in the Philippines as a single guy, I became friends with lots of filipinos, some of which I'm still in contact with today. We had great times out bar hopping and partying, going on dive trips, etc. They even invited me to the "People Power II" protests (but I decided that it was too hot to be standing around on an EDSA flyover)! After I met my wife, her brothers were surprised that I new where all the cool bars in Manila were!

As Graham mentions, there are loads of expats in Manila, but making friends with some locals could be very rewarding.