In the bedroom: Her vagina is the "peanut butter" whereas her anus is the "chocolate". It is fine to get some peanut butter in her chocolate but not the other way around. "Chocolate in the peanut butter" is this unfortunate state.

Usage outside of the bedroom:

Computer programmers may exclaim this when they mix up the binding of their duck-typed variables with incompatible variables for an unfortunate result.
"Oh no, I got chocolate in the peanut butter."
(said in front of co-workers in which whom only have experienced the bedroom version) "Oops, did I just say that?"
by logicmoo January 16, 2018
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when a dood covers his dick in peanut butter then he screws a girl annally making it a chocolate covered peanut butter pine cone!
dood i totally made her taste my chocolate covered peanut butter pinecone
by fgdsagfkhsadk October 12, 2009
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