Put on a false front and Simmer down

Simmer down and put on a false front are semantically related. In some cases you can use "Simmer down" instead a verb phrase "Put on a false front".

Simmer down verb - Become quiet or calm, especially after a state of agitation.

Put on a false front and simmer down are semantically related. Sometimes you can use "Put on a false front" instead a verb "Simmer down".