Succession

What Wu Long used, was a particular set of skills he invented and named "Soft Pleasure", included in the Path of Origin Pleasure, the third of the Seven Paths of Pleasure.

It allowed to soften, and even create a disparity between the perceived pleasure and the actual pleasure of his partners, thus allowing them to still experience pleasure while not really using much of their Yin Qi.

This was the reason Hua Ziyan felt a clear difference, but could not describe what it was as it was hard to put into words.

Of course, there was a weak point to these skills in that they were only suitable for foreplay, and not for full dual cultivation.

He designed it specifically for the situations in which a partner could not afford too much strain on their body either due to fatigue, injury or temporary lack of Harmonic Qi.