I wouldn't rule out some on here hitting the ball on the down in.. The forum seems a broad church of standard. :-)
But there were some funny ones in the olden days too. "Hitting it on the up" used to be heard a lot. A batsman is always hitting it on the up. When would he ever be hitting it on the down? (Thanks to Graeme Fowler for highlighting this.)
Isn't 'hitting on the up' supposed to be in relation to the arc of the bat, not trajectory of the ball.
I always thought that too.. aka, not waiting for it properly and so hitting it on the up.