This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
噣 combines 口 (mouth) with 蜀, which likely contributes the sound. The exact historical development is uncertain.
The left side is a mouth 口, and the right side 蜀 is a complex shape. Without a clear meaning, picture a mouth making an unusual sound represented by the intricate right component.
For チュ, imagine a mouth 口 chewing (チュ) on something, even though the meaning is uncertain: chew -> チュ.