When your opponent shoots in, if his head is
- down, you can help his head to go down even lower.
- up, you can help his head to go up even higher.
When your opponent's head is up but his body is leaning forward, there is an untrual angle between his body and his head. You can take advantage on that angle and make that angle larger. The "head down" is not any worse than "head up". It's whether your opponent allows you to have free arms or not.