
ohako |
not for PFS, obviously
Gruesome Gobbler (Ex): At 12th level, a gingerbread witch gains a bite attack that deals 1d6 points of damage for a Medium witch. As a full-round action, she can make a single bite attack that deals double base damage (2d6 for a Medium witch) and functions as if she had the grab and swallow whole special attacks, allowing her to grab and swallow a creature of her size or smaller. Her stomach doesn’t deal damage to swallowed creatures, but a living creature she swallows must succeed at a Fortitude save (DC = 10 + 1/2 her witch level + Constitution modifier) at the beginning of each of its turns or become nauseated for 1 round.
If a gingerbread witch successfully swallows a creature, her torso distends grotesquely and she is treated as if she were carrying a heavy load if the creature is the same size and a medium load if it’s one size smaller; regardless, she can swallow only one such creature at a time. Creatures two or more sizes smaller do not distend her belly, though every four creatures of a smaller size count as one creature one size category larger (she can swallow 4 Tiny, 16 Diminutive, or 64 Fine creatures). She can regurgitate a swallowed creature of her choice as a move action, leaving it prone in an adjacent open square. If she is struck with a confirmed critical hit while she has a creature swallowed, the swallowed creatures each take half as much damage as the witch does (this doesn’t reduce the damage the gingerbread witch takes).
Right, so, the good parts
a) You can bite and grapple and swallow whole a creature your size or smaller with one full-round action. That's some nice action economy, at least.
b) You can barf your victim into an adjacent 'open square'. Presumably this includes cliffs and barbecue pits.
c) A swallowed creature is grappled, but the swallower is not.
The bad parts (they're pretty bad)
a) your victim doesn't take damage while they're in there. For reasons...
b) witch hit points are naturally low, and witches don't have a lot of spells for boosting natural armor
So, say you swallow a living creature (hopefully you check them for sharp things and ways to change size first) and they're not dead. How exactly are you going to kill them? You don't want to hit yourself with weapons, there probably isn't a 'nauseated creatures die of too much vomiting spell', and you really don't want them alive and kicking in there.
Also, heck, here's a rules question. Say you cast a nasty touch spell. Can you automatically hit a swallowed creature with it? Can you even touch them at all without reaching down your throat?

avr |

It does look like a prison rather than a combat tactic for the most part. I'd allow the witch to cast touch attack spells on them (using the grappled condition not autosuccess) but I have no idea if there are any rules which apply there.
Many of the witch archetypes are there to emulate some nasty story rather than to be effective as a PC. This is one of them.

BENSLAYER |

If the Target is knocked Unconscious they cannot attempt to hold their breath - once swallowed there will not exactly be a lot of breathable air ... If they are Conscious then it will take longer and risk escape, although really this is for capturing weak, 1HD Commoner children that will have a difficult time. Add to this the Round by Round possibility of the Nauseated Condition preventing Attacks to escape and it could be hard for Opponents with a lower Fortitude Bonus, (especially if the Witch wears one of the Belts for Con+2/3/6 to up the D.C.).
On top of this a Witch can take control of the situation - hit them and their Ally inside gets hurt too. "Hurt me and the food-baby gets it!" "Thanks for tenderizing the meat - want to give it another bash?" "Ooo, they have stopped fighting back, they must be Unconscious. Thank you so much." Of course, if you are trying to go against the set-up with a Neutral/Good Alignment then capturing a known Enemy and forcibly transporting them to an unfavourable location (via the stomach express) before recommencing Combat is not too shabby. There are too many Opponents to deal with at once? Save one for later. A noodle-armed Spellcaster is dropping Fireballs left and right? Take them out of the fight until their minions have been dealt with or someone Casts an anti-magic Spell.