with your tongue in your cheek
US /wɪð jʊər tʌŋ ɪn jʊər tʃiːk/
UK /wɪð jʊər tʌŋ ɪn jʊər tʃiːk/

1.
con la lengua en la mejilla, irónicamente, en tono de broma
said or done in an ironic, insincere, or facetious way
:
•
He said he loved my new haircut, but I think he said it with his tongue in his cheek.
Dijo que le encantaba mi nuevo corte de pelo, pero creo que lo dijo con la lengua en la mejilla.
•
The comedian delivered his political jokes with his tongue in his cheek.
El comediante pronunció sus chistes políticos con la lengua en la mejilla.