Were Fang Covers (3.5e Equipment)
From D&D Wiki
A set of Fang Covers that most good aligned Lycanthropes use to prevent spreading Lycanthropy to foes while fighting in their forms.
While Lycanthropes of any alignment can use these Fang Covers those of a evil alignment usually don't care about spreading Lycanthropy to their foes.
While in their base forms most Lycanthropes keep their Fang Covers somewhere easy to reach and stick it in their mouths while changing form.
A Lycanthrope can't use Fang Covers unless they are aware that they suffer from Lycanthropy, When changing involuntary they must pass a DC 20 Reflex save to put the Fang Covers on in time, if the transform is voluntary they automatically pass the Reflex save, while in hybrid form they may take the Fang Covers on and off as a Standard action that provokes an attack of opportunity, they can't take the Fang Covers on or off while in animal form.
(Note) The Fang Covers don't add or remove damage from the Lycanthropes bite it just prevents spreading Lycanthropy.