A type of beak guard used in sexual activity to simulate the lips of a mammal for safer oral sex, often by softening and smoothening the tomia .

According to the FA descriptions of post #439652 and post #428529, the source Fur Affinity posts of which mark the creation of the concept, a beak sheath is a set of form-fitting polymer 'lips' that on contact with saliva causes a temporary chemical bond to the beak while saliva lubricates and 'inflates' the covers to simulate a mammal's lips, protecting their mate's delicate bits from their sharp tomia and producing flavored lubrication.

See also

• topic #31728 - relevant forum thread