The kipper's knickers is actually one of a set of nonsense catchphrases from 1920's America. It indicates something excellent, admirable or first-rate - NOT a female who's personal hygeine is in question as posted by iamamanufan on this site.
You think you're the kipper's knickers, don't you?
by The kippers knickers March 09, 2017
Hey look, here comes kipper knickers
by iamamanufan January 11, 2011