A couple things come to mind here:
1) This "coach" might have meant that you need to have a softer grip and therefore it feels softer at your release. The ball is like a canary, you dont want it to get away, but you dont want to squish it.
2) Once you have the soft grip from above, raise your back swing up and slow your timing so the ball is coming in late but still has speed.
3) Keep your hand on the inside part of the ball (so that the palm of your hand is facing away from your body), and as the ball gets to your ankle, flip your hand to the other side of the ball.
A soft release will make you a better shot maker and use less energy once you get use to everything. Knowing how to quickly move your hand around the ball will increase rotation and angle which can still be done with a soft release. And remember to roll through the ball. A softer release doesn't mean stopping your release the second the ball falls off your hand. Continue your swing until your elbow bends and you almost pat yourself on the back. Hope this helps you out some....
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HAMMERDOWN!!!