Y'all on?
Y'all on™ is a way of asking if someone is on or announcing that you yourself are on Xbox, while also making fun of Aeden Shimada.

Y'all in™ is another term derived from y'all on™ in which Aeden Shimada approaches us at a bar and asks if we would like to be apart of a series of daring heists.
Us: "Aeden we're in a party wanna join us?"
Aeden Shimada: "Oh, Y'all on?"
Us: "...Are you farkin stupid?"