YOU SAID:

Chris was looking kind of glum with a thumb in his mouth.

INTO JAPANESE

クリスは彼の口に親指で親指をかぶっていた。

BACK INTO ENGLISH

Chris had his thumb on his mouth with his thumb.

INTO JAPANESE

クリスは親指で親指を口につけていた。

BACK INTO ENGLISH

Chris had his thumb on his mouth with his thumb.