Hello. I can assist you with your question.
You cannot legally watch copyrighted material for which you didn't pay. You can use the following ways to find and download porn. You may come accross a great deal of copyrighted material by doing this, so please be carfeful not to download those.
The easiest way is with a Bittorrent client like Vuze. Once you donwload and install that, there are many sites you can go to depending on your preference. A couple examples are:
You can find one tailored to your specific interest by searching for bittorrent.
Also, there are file sharing services that require you download multi-part files, like Rapidshare. Sites like this are difficult to search, so there are third party sites that make that possible. One example of a file search is FileCrop.
And since these files are multi-part, it is easier with a utility such a JDownloader, which recognizes the parts and downloads them all for you.
Those are the best two methods - bittorrent and the shared file sites. I wouldn't recommend any others because they are not safe. Remember, you will see a great number of copyrighted movies on these sites mixed in with the others. So be careful not to download the copyrighted movies because it is illegal in most countries.
PS. I think this answer deserves a bonus, don't you?