portal mask
A face mask which functions as a portal in a similar manner to portal panties, often in conjunction with a portal fleshlight, to allow a penis, sex toy, or other object to be inserted through the portal into the character's mouth. Allows non-euclidean penetration, and, if used with the character's own penis, non-euclidean masturbation and autopenetration.
This tag implicates mask, thinking_with_portals (learn more).