The word "schnickelfritz" is a term of endearment of uncertain Germanic origin. It means something akin to 'rascal', 'scamp', or '
little chatterbox'. The word is usually used with
children, but can also be used between others who are close with each other.
Also, Schnickel Fritz is a folklore
character. Fritz was a rascally little boy. He also is mentioned in the Schnitzelbank song. (Google the song...I'm not chronicling it here.)