2-N Underhand Pitch
 

When I make a poor swing I "roundhouse"

2-N states that there must be a underhand pitch motion and feel. If there isn't then you are "Roundhousing"

How do you feel a underhand pitch, but at the same time you are trying to hit down and thru the ball?

Seems like the underhand pitch would make the left wrist bend.

The underhand pitch is 'through low point' - so the 'up' section isn't until after impact.

Like an upper cut punch to a spot under the ground (aiming point, ahead of the ball).

The key is that where you are directing force is under and ahead of the ball. Per 1-L-15