It's a pouch that can hold an infinite amount of items but the more she has the more her body grows for space. It is also at the surface of her skin allowing things to breath inside her but still keeps what ever it is safe from attacks. They can also look out of here body at what's around them like the floor or trees and lakes. They can also see her from the pouch that lays just beside her stomach she can also pull them to her head to come out they can also use her head to inside, and it's  even weirder her butt area as a second hole that allows for things to come in or out.

This wall keeps the organs and blood with in the dragon it can handle weapon and magic attacks but can't protect from the blast so they normally come out the mouth as a burp or out the butt as a fart sending a shock wave where they are facing.

Your lineage stems from a dragon progenitor. Choose the kind of dragon from the Draconic Ancestors table. Your choice affects your Breath Weapon and Damage Resistance traits as well as your appearance.

When you take the Attack action on your turn, you can replace one of your attacks with an exhalation of magical energy in either a 15-foot Cone or a 30-foot Line that is 5 feet wide (choose the shape each time). Each creature in that area must make a Dexterity saving throw (DC 8 plus your Constitution modifier and Proficiency Bonus). On a failed save, a creature takes 1d10 damage of the type determined by your Draconic Ancestry trait. On a successful save, a creature takes half as much damage. This damage increases by 1d10 when you reach character levels 5 (2d10), 11 (3d10), and 17 (4d10).

You can use this Breath Weapon a number of times equal to your Proficiency Bonus, and you regain all expended uses when you finish a Long Rest.

You have Resistance to the damage type determined by your Draconic Ancestry trait.

You have Darkvision with a range of 60 feet.