Used when somebody is completely unqualified for an opinion or position on a matter and should remove themselves. Generally the statement comes from someone more experienced on the matter to one that is not. The idea is that the inexperienced person has entered an area of knowledge too great for their brain and they should lay down because they are displaying elements attributed to fatigue saying nonsensical things.
Some non gaming person: "Those video games are the root of all evil of today's children"
Sane person with video game experience: " Aww just go lay down already."