breaking a neck is never in the intentions - however, the damage you may cause if it happens is so diresome (and the judicial consequences so diresome as well) that my personal suggestion is: if your very same life is not in the line, u stay away from necks.
If you're at a neck, you're threading in kills' grounds.
That's a strange attitude from someone who, and I quote
am with the Tantra way to initiation, with the ghora (the horrific), with the second path to enlightenment: for that path, you don't get illuminated by cultivating harmony or by removing desire, but by mastering the horrific. It's the path of the charnel grounds, if you ever heard of that.
It is neither better nor worse than the other way: yet, it is just another well established way to attain that goal...some guys have a preference for attaining mastery by confronting the brutal and the unpleasant. In this mindset, you are ready only when you master dread and fear - when all the daemons may come to you threatening you, and yet you're utterly ummoved.
You grow into the tempest - if the tempest, of course, doesn't kill or maims you first (which it has a regrettable tendency to do...).
So do you rock up to your Tantrist training sessions and say, "Right chaps, as per usual we're with the ghora today, path of the charnel grounds, confronting the brutal and the unpleasant, mastering dread and fear, remaining unmoved by the threats of daemons and growing into a tempest, etcetera and oh, yes, don't touch each other's necks."?