Don't throw a hissy fit

Meaning

A command for someone to stop overreacting or throwing a childish tantrum. It implies that their emotional display is excessive for the circumstances.

Dismissive, sassy

Used in a sentence

• If you don't get the toy you want, please do not throw a hissy fit in the store.
• The boss is going to throw a hissy fit when he sees the quarterly numbers.
• She threw a huge hissy fit just because we ran out of sweet tea.