This special attack allows a flying or jumping dragon of at least Huge size to land on opponents as a standard action, using the whole of its body to crush them.
Crush attacks are effective only against opponents 3 or more size categories smaller than the dragon (although it can attempt normal overrun or grapple attacks against larger opponents. A crush attack effects as many creatures as can fit under the dragon's body. Creatures in the affected area must succeed on a Reflex save (DC equal to the dragon's breath weapon) or be pinned, automatically taking bludgeoning damage during the next round, unless the dragon moves off them. If the dragon chooses to maintain the pin, treat it as a normal grapple attack. Pinned opponents take damage from the crush each round if they do not escape.
A crush attack deals the age table indicated damage plus 1.5x dragon's Strength bonus (round down).
Based on the entry in Dungeons & Dragons Monster Manual 3.5