Why were ancient women beaten naked when they made mistakes?

This is the family rule of a large family beating concubines in the Ming Dynasty.

(Ordering concubines) Lie on the bed, take off your skirt and trousers, and hit (concubines) five or six times with a bamboo board. The flapping position is not lower than the downward separation of the two strands (crotch) and not higher than the coccyx upward. -Take off pants and spank properly!

The status of ancient women was very low, especially concubines. This is just a fertility tool. Even if many concubines give birth to children, once they make a mistake, they still have to take off their pants and be beaten naked in front of their master concubines, with no dignity. As for why it is judged that this is not hitting the handmaid but hitting the concubine, it is because it is "on the couch." Lying in bed is the only "treatment" for the man who is "sleeping beside the bed", and he often avoids people. If ordinary handmaids make mistakes, they can't even get such preferential treatment. And in full view, lying on the bench (or on the ground) directly hit the big board. Just imagine, the maids are unmarried women, who are accused in public and naturally lose face. It is also a "warning" to other maids.