Inside a Creature's stomach
The inside of a creature 's stomach (even if it can swallow you whole) is not "unoccupied space" even if he hasn't eaten anyone today. The space is occupied by the stomach itself and when you're swallowed you're restrained because you're sharing that space and have no freedom of movement.
Therefore, spells, feats and traits that require an "unoccupied space" such as summoning, will not work inside a stomach.
Therefore, spells, feats and traits that require an "unoccupied space" such as summoning, will not work inside a stomach.
