Kapitel 96: “You’re the only exception.”

"What is it used for?"

  Robert looked into the cup more intently, which made his servant feel uncomfortable, though they understood why Robert was clueless about the bell-shaped cup.

Adopted princes like Ronard and Robert were not properly given sex education as it was thought unnecessary for them.

The maid cleared her throat before answering Robert's inquiry. 

"I-it is inserted into the lady's private part during menstruation. Its purpose is to collect menstrual fluid, my lord."

There is more to explain about the cup, like it can store an infinite amount of liquid and it was created from the magic tower, but the maid made it short and simple because of how clueless Robert was in regards to the woman's body.

"What's menstruation, anyway? What kind of disease is that?"

"It's not a disease, my lord! It is normal vaginal bleeding that occurs as part of a woman's monthly cycle."