I am pretty sure that the notion of "sexting" is pretty new to you. Let me give you the definition, via UrbanDictionary: "the act of text messaging someone in the hopes of having a sexual encounter with them later; initially casual, transitioning into highly suggestive and even sexually explicit. In a sentence: "He keeps sexting me saying how hard he is and how much he wants to tap my ass," Cindy said massaging her breasts unconsciously". Now you know!
SextingForum.net is a forum that will give you exactly that. It has only real members from around the world and it will show Snapchat usernames. Their boards will welcome you right from the beginning, on the homepage: introductions, general chat, Snapchat girls, Snapchat Usernames (as said above, where you can find people willing to chat), Snapchat Nudes and many more.
This forum is pretty active and it has 495.000+ total posts at the moment of this review, 180.000+ members and 33.000+ most online users at the same time. It is free to browse and to see all the goodies, still, if you want to interact with the community, you need to sign up, which is also free!