On Reddit, you'll find a subreddit that goes by the name of /r/Sex – as you might have guessed, this is where people go for civil discussion on all things related to eroticism, relationships and physical intimacy. With over 850,000 subscribers, it's one of the most popular NSFW communities and has one of the best user bases I've come across, where judgement is limited and support encouraged. /r/Sex has a great moderation team that keep the community tidy and free of spam, even if there are quite a few rules in place that might otherwise limit non-spammy content that they consider to be low-effort or not suitable to the subreddit.
Posts here range from recaps of first-time experiences within certain activities (such as anal sex), advice on how to prepare oneself for an activity and confessions from people that want a little validation from the community that they're not totally weird and a freak. Like I said before, /r/Sex is about positive vibes and helping people enjoy sex as much as possible – you'll get truth if you speak nonsense, but if you're open to advice or just want to offer your opinion without being rude about it, you'll be welcomed with open arms.
With specific regard to the sexiness of the written material here – it's not exactly masturbation city. You'll come across some interesting content, but for the most part, I'm putting it on this list because you might want to communicate with others about your sex life outside of just wanting to jerk off. Certainly one of the better – and well maintained – NSFW subreddits out there. Check it out and if you want some fun, be sure to search by 'controversial' – that's where all of the crazy stuff goes!