Man Sex. Yup, it has come to the point in Reddit's maturity that people call subreddits blunt, in your face titles like this. So yeah, /r/ManSex currently has just shy of 3,500 readers and was started two years ago by a user called Watch While You Sleep. It really doesn't have a whole lot of moderation going on and the premise here is to just enjoy men having sex.
Note that /r/ManSex is 100% gay and to give you a sense of how regularly new stuff comes in, there have been 10 posts in the last month. So yeah, not exactly ideal, but some users do submit their own material for you to enjoy. I'd say that while this is still worth checking out, it's one of the bottom-priority options for those that want some good quality man sex.
Check it out and see for yourself. Hell, you may even want to start contributing to the subreddit if you think you have what it takes to please /r/ManSex.