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.)