A past memory that causes severe twitching and gagging due to how utterly awkward the memory has become in the person's mind. Those memories are most likely associated to an ex-lover who is such an ass hole their previous actions enduce the milk of the memory.
Ahh, milky memory, milky memory! *gag*
Person #1: *twitch* Ahh remember that one time Jake asked me to get down on all fours and sing "Who Let The Dogs Out?"
Person #2: Ew, you never told me that milky memory!