[Maveh]

First of all most sites this method goes through will use either IRC or Bittorrent as the download method so if you don't like either of those your pretty much out of luck.

Now...

First go to anidb.info and search or browse for the hentai of your choice. To be able to view mature anime reviews and information you will have to register a free account and in your account options check to view +18 material.

Once you have found the show you would like to download look over the page and about half way down just under the description you should see a list of groups that have released their version along with their progress if it is a multiple episode OAV or Series. Click one or all of the groups listed to check for their website or IRC channel which will have information on how to download their releases.

With this method you will get high quality releases usually straight from the original DVD instead of the small time paysite junk that you get from most other places.

Enjoy.