The ability says this...
Prehensile Tail Many tieflings have tails, but some have long, flexible tails that can be used to carry items. While they cannot wield weapons with their tails, they can use them to retrieve small, stowed objects carried on their persons as a swift action. This racial trait replaces fiendish sorcery.
What's the extent of things you can pull out with this? can it pull out weapons? also, can it HOLD items? the way I read it, it's just a pesudo-quick draw. i read it to pull the thing out, and place it in your hand. but a player of mine was trying to just hold rods in his tail and use them as if it were a hand, which i dont think RAW supports. It lets you draw things quickly, but cant hold them or count as a 'hand' for the purpose of using them. maybe at the most i'd let them hold it, but not USE it while in their tail. thoughts?
I don't think you can come close to a RAW definition, I would interpret as passive rod ok (eg metamagic) , holding sword not ok (since it is not small), using wand not ok (since it would be a weaponization of the tail. Also nogo on a small shield, since it would be weaponization.
So, nogo on weaponization, non-small, go on Holding/retrieving.