bulbus glandis; knot (of a canid penis)
Anatomical term for the bulbous structure at the base of the glans in canids and some other mammals, often referred to as the 'knot' in breeding contexts.
During canine mating, the bulbus glandis swells to maintain the tie.
Compound of 亀頭 (glans penis) and 球 (ball, bulb), referring to the bulbous structure.