Xiang Kun has ample experience resisting the urge to drink blood, so he is extremely sensitive to the nuances of this feeling.
He assessed it closely, trying to identify the source of this difference.
The average person's control and perception of their own body are very limited. For example, apart from feeling hungry, discomfort, or the sensation of eating, it is tough to perceive the presence of the stomach and nearly impossible to control its movements actively.
Not to mention more intricate organs or smaller parts that due to physiological structure and nerve distribution are hard to perceive and control. The same applies to muscles we don't often use, parts that can be compensated by other sections, which we often cannot feel. Just like how someone who hasn't exercised much doesn't feel their pectoral muscles engage when they first start doing push-ups.
