Reposting since this post broke no rules and is genuinely an attempt to help people even if the shitty drawing might seem like a troll
I believe I genuinely am the only person to hold the controller this way, and everybody makes fun of me when I show them this, but don't knock it until you try it.
Controller turned 90 degrees, right hand on the analog stick, left hand on the a/b/c buttons. The left index finger can hit the R button and the bottom of the left palm can hit the L button effortlessly, plus you got Z right the right index finger.
It's more or less the same as the intended way to hold it except the right and left hands are reversed. You can also hit a lot more button combinations since you have some more fingers available on the left hand, whereas you ordinarily would be using just your thumb on the right hand.