Supple
From Gomerpedia
Supple is a word used to describe only two things apparently: necks and breasts.
Example
DENTIST 1: His teeth are supple.
DENTIST 2: What the hell are you talking about?
DENTIST 1: Is supple the word I'm looking for?
DENTIST 2: Definitely not.
DENTIST1 : How embarrassing.
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