Guide Book Entry
It is the root of mandragora, the plant-type monster with roots that has a female form. It has potent medicinal effects, and monsters use it as an ingredient for various obscene drugs such as aphrodisiacs and stamina boosters, while humans value it as an ingredient for a panacea to cure various diseases. However, among humans, especially in anti-monster states, it's a precious item in extremely short supply.
A mandragora's roots keep rapidly growing when she receives a man's spirit energy. And the stuff used as an ingredient for medicine is basically roots that were cut after growing too long. Cutting roots that grow as an extension of the feet may look painful, but to the mandragora herself, the act of cutting the roots after they've grown too long is something similar to how humans clip their nails. They're easy to cut, and it doesn't seem to cause any pain whatsoever, so please relax.
Also, when sucking mandragora's root, it has a mysterious taste that's both slightly sweet and slightly bitter that can be addictive. It seems people that like the taste find it unbearably good. In recent years, mandragora's root has been sold not just as a medicinal ingredient, but also as a cooking ingredient.
The flavor of the root comes out through sucking, but if it's a clipped off root, as a person is sucking it, the taste will gradually grow fainter until eventually the taste completely disappears. However, the unclipped roots of a mandragora herself will retain a thick flavor no matter how much one sucks, and it's possible to keep sucking them for as long as one pleases. Many of the husbands of the mandragoras were captivated by the charm of these roots, and it's said that they'll suck the mandragora's roots whenever they have a spare moment. There is an increasing trend for guys with a root fetish to desire to marry a mandragora due to having been enthralled by these roots.
Moreover, as mentioned before, the roots don't have any sense of pain at all, but just as you might expect from a monster, they're extremely sensitive to pleasure, and they say having them sucked feels very good. Supposedly every time their husband takes a root in his mouth and licks it will cause their entire body to shiver with pleasure, and experience rapturous delight and ecstasy.