Encouraging someone not to be excited
Pull yourself together.
Don’t get excited.
Don’t get all excited.
Don’t get all worked up.
Don’t blow your stack. (slang)
to blow your stack = to lose your temper; to go crazy Don’t lose your cool. (slang)
Don’t blow your cool.(slang)
Don’t blow a gasket.(slang)
Don’t go into hysterics.
Don’t go into hysterics on me.
Don’t fly off the handle.
Don’t pop your cork. (slang)
to pop your cork = to go crazy
Don’t work yourself into a tizzy. (informal)
a tizzy = a dizzy, confused state
Don’t run around like a chicken with its head cut off (informal)
Would you restrain yourself?
Get a grip (on yourself), (informal)
Would you get a grip? (informal)