bite your tongue
US /baɪt jʊər tʌŋ/
UK /baɪt jʊər tʌŋ/

1.
op je tong bijten, je inhouden
to make a conscious effort to avoid saying something that you want to say, often because it would be inappropriate or cause trouble
:
•
I had to bite my tongue to keep from telling him what I really thought.
Ik moest op mijn tong bijten om hem niet te vertellen wat ik echt dacht.
•
She wanted to argue, but decided to bite her tongue.
Ze wilde ruzie maken, maar besloot op haar tong te bijten.