animal_penis - Tag used for penises that exclusively belong to animals.

humanoid_penis - A penis that has the appearance of a standard human phallus.

canine_penis - A penis that resembles a canine penis. It is usually contained within a sheath. The base of the glans swells like a large bulbous knot when erect.

equine_penis - A penis similar to that of an equine penis. Characterized by a distinctive blunted head, mottling of colors, a flared or "mushroomed" head, a medial ring, and/or a ring of flesh near the sheath.

feline_penis - The feline penis is a type of tapered penis which has (depending on species) anywhere from a few to hundred sharp, backwards-facing barbs that stick out from the shaft during sex. Notably short and pointy compared to most species, it also features an extended sheath (not to be confused with medial ring).

hybrid_penis - This tag is applied when a penis has two or more features of different types of penises.

knotted_penis - The bulbus glandis, also colloquially known as a knot, is an erectile tissue structure on the penis of canid mammals. In reality, the knot only swells up moments before ejaculation (knotting), causing the giving and receiving parties to be stuck for some time. In fiction, a knot may be present at any moment. They tend to be present with any erection.

foreskin - loose fold of skin that covers the glans of a penis; it is a continuation of loose skin that covers the entire penis and scrotum (which is part of the balls).

medial_ring - Medial ring is the term for the ring running around the midsection of a penis. Usually on an equine character, but also seen on some cervines.

veiny_penis - Prominent/visible veins located on a character's penis. This is usually associated with humanoid_penis, but not always.