Snakes are not like dogs and cats though. They live on instinct. They probably prefer to perch on humans only because we are warm. (which is why even my cats choose to sleep on and around me at night. We humans are merely walking heating elements) When they are "cuddling" up against your neck, under your hair, they are not being affectionate. They are simply seeking the warmest part of your body since room temperature is a bit chilly for them. And kissing (by means of tapping their nose to a part of your body or flicking their tongue and it touches you) is probably just them exploring their surroundings. The smells coming from your body (smells coming from your mouth) change all the time and when a snake smells something different, it has to investigate. When you are holding them and they refuse to leave you to go to another person that is probably because when a snake has found a nice warm spot, they are not likely to leave it as long as they are not being threatened or are not disturbed. This does not mean they prefer you specifically, they are just comfortable where they are and prefer not to expend more energy in finding another spot.
I don't believe ANY of my snakes can show affection. We want to think they do because we as a species are social and display a wide variety of emotions. So when we have an emotional attachment to our snakes, we naturally expect some kind of response back (kind of like grooming in cats.) Any action that is based purely in instinct (seeking warmth, smelling their surroundings, etc) we take as affection (kissing, cuddling, not wanting to leave our hands.)![]()