look up any word, like tinder bombing:
 
1.
The act of inserting a thumb into the anus during intercourse. Inspired by the Happy Day's character,Arthur Fonzerelli, who was fond of giving the thumbs up and uttering "Aaaaaaa(nus)."
"We were doing it doggy style when Christian decided to give me a dirty fonzi! I felt so violated!!"
by Madamasselle March 01, 2003