From Zappa Wiki Jawaka
Hratche-plche is a vocal sound that is featured twice in Zappa's work. In both instances is it used in a sexual context.
- In the song Brown Shoes Don't Make It it is sang four times after the line "On a rug where they walk and drool past the girls in the office". The sound is made again after the line "Back in the bed his teenage queen is rocking & rolling and acting obscene. Baby! Baby! Baby! Baby!".
- At the end of Florentine Pogen the sound "Hratche-plche" can be heard again after Zappa's lines: "Chester's gorilla's she go... "
- An analysis of One Size Fits All by Ben Watson, where he notices the similarity between both sounds. (http://www.militantesthetix.co.uk/zappo/OSFAweb.htm)