发脾气to fly off the handle

耍脾气to throw a tantrum

• 小孩子又使性子了。

  The child is throwing another tantrum.

• 他动不动就对大家使性子。

  He flies off the handle at everyone at the slightest provocation.

• 有意见就好好地讲，何必使性子。

  There's no need to fly off the handle. If you have a suggestion just say it.