Cats, with their smart and petite figures, can always easily capture people's hearts. Sometimes, we find that this little guy kisses us on the lips, what is the reason behind this?First of all, we need to have an in-depth understanding of the cat's behavioral characteristics and habits. Cats, as animals with extremely keen senses, perceive everything around them through their senses of smell, hearing, sight, and touch. When they feel safe and close, they express their emotions in a variety of ways, and kissing a human on the lips is one of them. 
Secondly, let's take a look at the mystery of the cat's mouth and saliva. A cat's mouth is filled with scent glands that secrete special odor substances. When the cat kisses us, these scent substances are left on our **, conveying the cat's trust and emotion to us. In addition, cats' saliva also contains hormones called "pheromones", which have a soothing and relaxing effect, making the emotional bond between cats and us stronger. 
Furthermore, we can't ignore cats' body language and social habits. Kissing a human lip is a positive expression for cats, meaning they feel happy and satisfied. At the same time, it is also a way to socialize with each other. 
In summary, cats kissing our lips are a combination of factors, including their behavior, oral and saliva characteristics, body language, and social habits. When we understand these factors in depth, we are better able to build a deep emotional bond with our cats. At the same time, we should also pay attention to our own oral hygiene to ensure that close contact with cats does not affect our health.