[quote=LeeRoy]
How would a downward strike even work? That doesn't seem possible.
[/quote]

Way I imagined it, Snar is under Sukoh. Then he twisted his head under himself to his jaws around his waist. (it originally looked more like he was biting his actual lower back.) 

Snar's arms are already raised over his head, he simply dropped his elbow downward. If his arms had been at his side then it would have been more akin to a side elbow.