chew the cud
齝 centers on the act of chewing the cud, a specific digestive process in ruminant animals. The meaning is narrow and technical.
齝 combines 齒 (teeth) with 台, which likely contributes a phonetic element. The character is rare and its exact historical development is uncertain.
The left side 齒 means teeth, and the right side 台 looks like a platform. Imagine a cow on a platform, slowly chewing its cud with its teeth.
For チ, picture a cow chewing the cud while sitting on a platform, and think of the sound 'chew' — the 'ch' sound cues チ.