I am in search of the title of a movie that was on cable when I was young. The movie was showing on one of the movie channels in the early 80's. It was about a boy, I think that he couldn't grow up. The main thing I remember about the movie was him eating pop rocks from a girls navel. Not much to go on o know, thought it was called little drummer boy but I can't find anything like it under that name.

The Tin Drum / Die Blechtrommel
The Tin Drum (1979) - IMDb (http://www.imdb.com/title/tt0078875/)

According to wikipedia it's not pop rocks but "sherbet powder" that he eats from the navel, but other then that it fits your description.