Mouthy types speaking of evil on both sides backtracking (4)

I believe the answer is:

lips

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'mouthy types' is the definition.
The answer and definition can be both man-made objects as well as being plural nouns.
Maybe they are linked in a way I don't understand?

I cannot understand how the remainder of the clue works.

Can you help me to learn more?

(Other definitions for lips that I've seen before include "Brims, rims" , "Fleshy folds of tissue" , "Rim of the mouth" , "Top edges of vessels" , "margins" .)

I've seen this clue in the Irish Times.

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