The Yin Yang Hot Springs is a popular location within the Boundless Yin Yang Sect. It's a place where disciples of all ranks can gather to soak in an outdoor hot spring filled with spiritual water to relax their bodies.
However, that's not the main reason why most disciples visit the Yin Yang Hot Springs.
The Yin Yang Hot Springs is actually mixed-gender, meaning that both men and women will bathe in the same place.
The main purpose of the Yin Yang Hot Springs is to let the disciples show off their body.
If a female disciple sees a male disciple with a sword that's their ideal length, they could approach the male disciple and ask if they want to cultivate later.
As for the male disciples, they often look for female disciples with their desired body type.
The reason Su Yang wanted to visit the Yin Yang Hot Springs was a simple one.
He wanted to show the disciples his perfect sword. In other words, he was there to brag with a purpose.