Earplug

An earplug is something placed in the ear to restrict someone's ability to hear, usually a piece of soft rubber. In a BDSM context, this will often be as part of a sensory deprivation scene and the ear plugs may be supplementary to an isolation hood.

Ear plugs are never 100% effective; even if the ear is well filled, sound can travel through the bones of the skull.

An alternative is to fill the ear with molten wax and allow it to set; indeed the ear may be partially filled with wax and topped with an earplug. Very low-temperature melting wax should be used to avoid damaging the eardrum.