A youtube D.J. resides to playing music via youtube for enjoyment or substitution because they cannot afford a stereo system.

When you eat dirt for the first time and leave your family to build a shack in the woods

Can be used as a noun or a verb (e.g. youtube deejaying) and denotes someone who uses Youtube as a jukebox.

The act of having 2 (or more) tabs of youtube open with music videos pre-loaded on to them. Before the first video stops the youtube DJ will hit play on the next video transitioning from one song to the other seamlessly ergo eliminating the risk of awkward silences. often used in small partys and gatherings of acquaintances where there is no sound system present.

The person in the room who's in control of the flow of Youtube videos. Talented Youtube DJ's who take themselves seriously have to be constantly updated with the most fresh videos around, sense the video's "feel" and "timing" as well as the viewers' "vibe" in order to create a good atmosphere, and the ability to keep up with youtube-DJing for hours.