No matter the world, prying into another person's privacy was never particularly polite. Mortals had weak senses, yet still observed such rules as "see no evil, hear no evil, speak no evil, do no evil." Cultivators possessed all manner of bizarre perception; Wu Shiqin, for instance, could "see" Electromagnetic Waves across most frequency bands, while Ai Changyuan could accurately measure the mass of all kinds of things through gravity. Under such circumstances, if there were no universally recognized bottom line, cultivators would probably not dare leave home without layering themselves in several hundred barriers against prying.
Among those rules, "one must not use spiritual sense to probe another's body" was a particularly important one.
After all, the secrets of a cultivator's cultivation methods and practice lay within the body. Probing them was tantamount to making enemies of the person being probed, their sect, and their Lineage. And, to put it crudely, spiritual sense was the feedback of spiritual energy, while spiritual energy was the exponent of energy, highly sensitive to sound, light, electricity, heat, and magnetism. Using spiritual sense to examine another person's body could reveal details more delicate and direct than touching them with one's hands.
The cultivation methods on Bo Xiaoya's body were nothing more than the Yao Ding Suanjing and the Geometry Book. Limited by her realm, she had never learned the Bo family's profound methods, so Bo Xiaofeng did not care much about others peering into her cultivation—but that little bastard actually dared to do this to my little sister... Aaaaaah!
Su Junyu silently retreated two steps. Bo Xiaofeng in this state was absolutely not someone to provoke, and he was inexplicably disgusting as well. After mentally passing such a malicious judgment on someone, Su Junyu turned his attention back to Wang Qi's mathematical deduction.
Terrifying.