I'll give it a go.
Swallow Whole (Ex): A draeden can try to swallow a grabbed opponent which fits in its Engulfing Maw by making a successful grapple check. Once inside, the opponent takes 10d10+45 points of crushing damage plus 8d12 points of acid damage and travels 140?? ft toward the draeden's central body per round. No creature with speed less than 80?? ft can climb out of the draeden's maw by making an opposed grapple check; however, a successful grapple check prevents the victim from progressing farther toward the central maw. A swallowed creature can cut its way out by using a light slashing or piercing weapon to deal 60?? points of damage to the interior of the tube (AC 90); if the damage is not done in a single round, the victim must maintain position by winning opposed grapple checks. Once the creature exits, muscular action closes the hole; another swallowed opponent must cut its own way out. A victim that reaches the central gizzard takes 100d10+45 bludgeoning and 80d12 acid damage per round. A draeden can hold an effectively limitless number of creatures up to Colossal size.