No one knows how it started but this word is becoming very popular on social media as a fill word that can mean anything from "cool" to anyone of many derogatory words.
The most common uses of these sentences happen (mostly to me) while laying in bed at night.
"Oh, that one boy, Shiggity Sean, what a dreamy man. I can't wait to stare at him later... Oh, Shiggity Sean!!!"- Mom walks into bedroom asking if you are okay, you say yes, she leaves, and you keep fantasizing about the almighty Shiggity Sean.