One of the weak spots on the human body is the neck. If someone has you by the throat it’s immediately bad, likewise a blow to the back of your exposed neck is life threatening.
There are dozens of cultures that have some combination of bowing and hats off (think “armored helmets off” as the early variant of what turns into the modern “hats off”) from the social inferior to the social superior. It’s a social submission signal to expose physical weakness.
Likewise in the animal kingdom there are readily observable submission signals where the weaker literally bows their head to the stronger. The message is clear “ok I get it, you’re in charge here and I’m better off aligning myself to you rather than trying to compete with you”. Humans are much the same, in a stand off building towards a potential fist fight between two guys, the first guy that drops his head to the other loses the stand off. The social signal of submission avoids the physical fight happening.
Likewise it is a dominance signal to touch someone else’s neck. Touching the front of the neck is of course extremely hostile and social status and potential legal pitfalls tend to be ignored in favor of establishing an airway by any means necessary. I’m more talking about touching the back of the neck. Anyone that touches the back of your neck is announcing very clearly that they are expecting your submission.
Ever noticed how much women like their necks kissed? Especially that sneak up behind them and wrap your arms around them and gently nuzzle on their neck. Bonus points for doing this when you kind of trap them up against the kitchen counter when they are making you a sandwich.
The other move is a very light hold on the back of the neck when you are kissing or making love. Note I said “very light hold” and not “crush her windpipe” or “shake her by the neck like a rag doll”. It’s just a social signal that implies physical dominance, the entire point is that you don’t actually have to prove that physical dominance by a physical confrontation.
So anyway… neck kissing… maybe some ladies out there just discovered they are more wired for submission than they first thought….