get on his high horse

Get on his high horse (or her high horse) is a phrase that means to behave in an arrogant or condescending manner. Telling someone to get on his high horse is the opposite of getting off their high horse in which you want them to stop acting superior. If you want someone on his high horse, he will behave in an arrogant way in order to achieve something great. This is also sometimes used in a more negative, sarcastic manner.