I always have pretty weird dreams but I remember taking off the Joycons from the Switch then putting them on the grip. I didn't like it so I took the right one off and used it on it's side to play Mario Kart.
From my dream I have the following leaked info:
•The Joycons need to be in a certain position in your hands otherwise they dig into your fingers
•The rail bumpers (think they're called Z something on Ninty consoles?) work well but the edges are sharp.
I drew an illustration in MS Paint to help: Link
Discussion started at here by CoolJWR100