To know why “kissing” may not need the mouth, we need to know what is love–“愛/ai”, because to “kiss/吻” cannot be separated from love.
The Chinese writing underwent a significant simplifying by the current government in the nineteen fifties. So the traditional unsimplified “love” is written like this: “愛 “. The later simplified version is this “爱”. The traditional script has “心/heart” as its radical. The later vision has “爪/claws” as its radical.
From this, you can see that the original love tells you to love with your heart. If a person has love in their heart, even if they do not express it with kissing, they can both know that it is there. Even when the one wrongs the other, they still won’t become vindictive.
However, with the other love, from the claws and without heart, one may kiss with the mouth, or touch like a claw, where else will it not go?
No wonder, Paul says in the Bible, never mind about whether one has had circumcision in the body — signifying the removal of the lust of the flesh, the key is circumcision of the heart. Or else, even though you may appear to follow the rules to the tee, but inside you have every fleshly lust, what good is that?
Alright now. We’ve said a lot, but we do not intimate that it is better to not kiss, not at all. We are just trying to express that different cultures have different historical background. Not one culture is better than another. But we can take the good of each and learn to be more free and happier.