Assuming that first kiss feels just right, then the brain nerves used for hearing, seeing, smelling and tasting are in overdrive; collectively affecting the expression on the lover’s face.
As the kiss heats-up blood vessels expand to allow more oxygen to the brain, breathing becomes deeper, irregular and pupils dilate (perhaps explaining why many lovers close their eyes).
Invariably there will be tongue contact, more often than not initiated by the male but more about that later. The tongue allows us to sample our partner’s taste with the assistance of over 9,000 little bumps or taste buds spread across its surface.
All five senses are sending messages to the brain; that is, tens of billions of nerves are firing rapidly throughout the body.
Lips are very sensitive to pressure, warmth and cold; they contain the highest concentration of nerve cells on our body. There are over 100 billion complex nerve cells liberally spread throughout the lips. They are the gateway to tiny neurotransmitter molecules that help trigger hormone release including dopamine, oxytocin, serotonin and adrenaline.
Gawd Damn!!! Science is sexy!!!