/r/TittyDrop is one of those subreddits that has produced a niche and interest in certain activities just via the sheer quality of the content and regulation of the material. The premise is simple: all posts are to include chicks getting their tits out that make them drop or jiggle at the same time. It's not the easiest thing to describe, but if you head on over to the subreddit and check out a few submissions, you'll soon realize exactly what it is I'm talking about.
There's a lot of amateur material here as well as professional content: pretty much any desire you could have is taken care of with the filter submissions too so you can hone in on reveals, flashes, 'classic drops' and other types of subreddit material.
New posts are made about once every four or so hours, giving you the ability to check back on a daily basis for some new titty dropping goodness. All in all, not a bad place at all for a very interesting and unique fetish.