I've posted a couple of reviews in Tokyo, if that's where you'll be, including one "soapy massage" place that I recommended.

Japan is a bit different that other places in Asia for P4P.  There are many places that  are "Japanese Only", so don't get discouraged if you have some trouble getting into some bars.  The Japanese love the girl bars where they pay big bucks to sit and talk with a girl, but unless you are Japanese, or perhaps speak Japanese, you will not get in.  Sometimes, if you have a local Japanese friend, you can.

Assuming you are not Japanese, and you do not speak Japanese, there are still a couple of good options depending on what you are looking for.  I think the best escort service is asian mystique.  Google it for the web site - and many of the girls are reviews here (several my me!).  They are outcall only, and cater to the non-Japanese folks.  Very reliable and dependable.

For massage, oral, bath, and everything except fs, NYNY in Ueno is  popular.  The fee is reasonable - around 10,000 yen.  Girls are middle aged but very service oriented and provide a good time - not models by any stretch of the imagination, but adequate.  FS is prohibited, and they want to make sure you know this so there is no problem.

For areas such as Roppongi or Shinguku, there are many non-Japanese bars, and the people outside trying to get you to come to their bar.  Most of these are complete ripoffs and are only there to take your money.  You will spend a fortune and get very little.  I avoid those, and just go to the regular bars in those areas.  You can meet regular Japanese girls that want to practice their English, and maybe you can make a new friend.

Hope that helps - if you have specific questions, just ask and I'll try to help.

JS

They have these clubs where you can act out fantasies, like feeling up a chubby girl while on a commuter train.
http://www.pinkboxjapan.com/book.html