When a squirrel dances and taps his feet to a little tune while his ball bag swings back and forth. or:

When you get overly excited about something but don't want to overtly express your joy.

zone-x.com/deez_nutz as an example

A portmanteau of carpe diem, a Latin phrase that means “Seize the Day!” and DM, which stands for Direct Messages. This word means seizing the day via DMs.