Noun. Portmanteau of "next" and "sexting." Present participle of the verb "to snext". The act of sending explicitly sexual text messages to a person directly next to you; sexting with intense proximity.
Guy: Wassup girl, wanna send me some dirty pictures and/or sexually explicit text messages over medium-to-long distance?
Girl: I'd love to, but wouldn't it be better if we snexted instead? I crave your warmth and love a good sext, but my goodies are on lockdown.
Guy: Totes! Snexting is the ultimate compromise!