Sounds odd, but I've been slowly progressing at my coin roll, but realize watching what I'm doing might not look good.

Anyone practice the "feel" by purposely not watching the hands, or closing your eyes?

Lastly, one thread indicated that having a little moisture on the back knuckles keeps the coin from sliding (I agree), but how do you insure this in a performance setting?

Practice till it's second nature.

Coin roll while your watching TV, eating a burger, driving, talking on the phone, etc....

Sometimes I do a coin roll while talking , reading a book or operating a computer, like smoking. I did so even riding a bicycle! (You shouldn't do that!)
If you intend to perform a coin roll in a show, you may do with both hands, alternatively or simultaneously.

And about lack of moisture, while I hate to say it as an advise to a close up worker, there is a point given to me by a stage performer. That is to drip very little Coca Cola on your hand before a performance. This was originally an advice about multiplying billiard balls.
Yes, that is not good method upon a close up table. But in emergency, I think that is one of choices.

Practice makes perfect!

...I've been known to lick the back of my knuckles before a coin roll to ensure proper 'sticking'. If you aren't the licking type, maybe the cola.
-Casey