When someone you're sexually interested in send you a late-night request for dirty talk, resulting in a session in which you help them masturbate and get some post-event fun. Usually occurring after midnight during the hours when booty texts and booty calls occur, and often motivated by alcohol, booty sexts are great for people in long distance relationships, people for whom a booty call would be unfeasible, people having affairs, and lazy people. May or may not be accompanied by dick pics or nudes.
Man, I got this awesome booty sext last night from this girl I'm into, I think I turned her on. Maybe we'll do more IRL later.