expression
zip it!; shut it!; be quiet!
Colloquial command telling someone to stop talking, literally 'zip your mouth'. Often used in informal, sometimes playful contexts.
See also: チャック
うるさいなあ。口にチャック！
You're so noisy. Zip it!
expression
I'll shut up; I'll keep quiet
Colloquial expression used by the speaker to indicate they will stop talking, often after being told to be quiet or realizing they've said too much.
あ、ごめん。口にチャックするね。
Oh, sorry. I'll shut up now.