This is a VERY GOOD blog with many pictures that I had never seen before.

http://yourbootblack.tumblr.com/tagged/ballbusting

You can also just look for balls. There are more pictures, not all of them having to do with ballbusting. But there are a couple of ballbusting pictures here that are not included in the ballbusting tag above.

http://yourbootblack.tumblr.com/tagged/balls