I usually have my left hand laid to the left and use my fingers. I find it more accurate to put my whole hand over the ball and it seems to work better than way.
Wow this thread sounds perverse. 
Anyway, how do you hold your stick?
left index and middle finger around the balltop meeting with the thumb and ring/pinky on the right side of the joystick shaft (think drunken boxer fist).
Helps with throwing the joystick to the left from the added force of the lower 2 fingers.
Between my thighs
or are you talking about while using it to play a game?
Double Entendre 
i use two hands…
ITT: Sexual innuendo, and someone who can’t find their search button.
Right hand on the joystick, left hand on the table, and third arm slapping against the buttons.
…That’s what she said
Man I have such a hard time with double quarter circles when I’m on the left side. That reason alone has turned me off of competitive play for the time being. I need to find a grip and stick with it.
Make sure you keep your stick lubed at all times.
Best to hold the stick firmly, but not too firm. You kind of want to have a loose hold without jerking it around too hard or your moves won’t be able to get off on demand.
You want to make sure you have total control at all times, though there’s nothing wrong with just slapping it around once in awhile and mash out those killer combos.
Don’t forget to clean up when you’re done.
hold it gently, but firm and cup the ball in your fingers, keep in mind its all in the wrist.
as above said keep your stick well lubed you dont wanna rub your stick raw.
im referring to the cherry top sticks BTW
bat style tops you can go buck wild and raw with it since its so sturdy.
usually i use my whole arm to move it around, causing my arm to get tired so i have to switch.
i usually keep a towel handy in case i sweat too much