Thou shalt delete all evidence
You should really delete a racy pic from your phone immediately -- sent or received. But if you live life on the edge, just don’t let your friends or grandmother scroll through your pictures. And always, always, ALWAYS keep the first photo on your camera roll PG. If you have a few hall-of-famer photos you want to hang on to, store them in Private Photo Vault, an app that requires a password for viewing. For the rest of you, take a long, hard look (lol) at your photos of nether-region naughty bits, then delete all traces from your texts, camera roll, and "Recently Deleted" folder. Or, just don’t send a photo of your penis at all. Because, newsflash: women generally don’t find them hot.
Thou shalt recycle wisely
Capturing the perfect shot takes 20 minutes and a great hair day. Since sexting is often initiated when one party is bored and seeking immediate validation, recycling your favorite photo is bound to happen. But screenshot the pic first, then send that version to sidestep the 2012 timestamp.