A thong berry is what happens when you think you're done with your period, so you put on a thong, but you end up with a congealed blob of gooey uterine blood stuck on your skank floss.

Internet persona(s) who happens to follow you and you happen to follow them back and maintain communication with and have a mutual liking for eachother whether it be friendship wise, etc. (Mutuals if more than one mutual)