Forgot to mention, as the heli starts to move forward, the left side of the "disk" is moving into faster air, and the receding blade is moving into slowing air creating less lift. The action reacts 90 degrees to the force, so the left side with more lift will act on the nose and less lift will act on the tail. Essentially, the heli will want to raise the nose. You will have to give a little nose down and decrease the collective.

When you slow back into a hover, you will need more collective again.