Playing around the neck, especially rough, can be a bad, bad thing. Dangerous? Oh yes. But in BDSM, we like to flirt with fire (figuratively and literally), which means normally "bad" things can be utilized in play. As always, communication is vital, and if someone has neck issues, I recommend caution, or even avoiding rough neck play altogether. Your mileage may vary.
Of course, the first real "neck play" is, well, necking! Heavy petting tends to involve lots of contact with the neck. Kisses, nibbles, bites, the sensation of your partner panting in pleasure against that sensitive skin. The nerve endings are so sensitive there, and it's definitely on the foreplay road map for most!
In play, the neck becomes an important tool. A firm hand around the throat, beneath the chin to tilt up your head, can mean, "Pay attention!" or "Focus!" A grip on the back of your neck is more directive, still a very dominant gesture, but it can be soothing or leading, depending on the pressure used, and which direction the dominant party pushes.
When laying down, the messages are slightly different. A hand to the throat when you're on your back can be an order to stay in place, an order to focus, or both at once. Stroking the throat can be a sign of affection and approval. A hand (or shiny, black leather boot...Mmm) to the back of the neck when you're on your belly means "Stay!" or "Submit."
That's merely placement. Then there's pressure, varying degrees of it, though of course one should be quite careful with not putting too much pressure in the wrong spot. Keep pressure very even, and keep in communication about how it feels.
A light caress can be very seductive and very soothing, lulling the submissive partner and giving them more reason to trust. A firm grip can be titillating, attention-getting, and incredibly bonding. It all depends on the energy of the scene.
The dominant isn't the only partner to play in the neck region! There are submissive gestures as well. Lightly kissing, even lightly nibbling, the dominant's neck, nuzzling it and rubbing your face against it, are all more submissive gestures. It also indicates trust from the dominant to the submissive. Remember, the dynamic is a two-way street, even if it looks like only one gives while the other takes.
From gentle caresses to firm interactions, the neck is a source of pleasure, communication, and trust. Use it wisely!
(Image within the text is not mine, but is linked to source)