i do not think it is instictive because not all human populations pratice it in anyform, i read before that some Amerindians were confused by its meaning and simply saw it as unhealthy, calling Europeans a word that ment "Dirty Mouths" as to their frequency in kissing, i do not remember the term
This is the most interesting form of "kissing" i've heard of as recorded by Darwin in Malaysia
"The women squatted with their faces upturned; my attendants stood leaning over them, laid the bridge of their noses at right angles over theirs, and commenced rubbing. It lasted somewhat longer than a hearty handshake with us. During this process they uttered a grunt of satisfaction."