Head Tilt. This is a Tango Topics described error that happens for both roles.
For the Lead it’s a tilting of their head either into and towards their Follower, sometimes resulting looking at the floor. Usually Head Tilt there is d0wnward pressure with the head against their Follower’s head (tsk, tsk, tsk); Or away from their Follower for fear of getting too close to them, so they tilt their head away. Sometimes, from a beginning and intermediate stand point, the Lead will tilt their head away to watch the open side turn or to ‘make room for’ the follower’s head. Again, these are errors.
From the Follower’s side of the equation, Head Tilt happens for a variety of reasons. The one that is most notable, bad breath on the part of the Lead. Still another that they’re a full head too small for their Lead so that will turn to the side, and tilt their head’s into their Lead. Thereby, usually, causing a slight but noticeable curvature of their spinal column, resulting in a slight pulling away in Close Embrace. These are just a couple of reasons, there are more.
In either case, dancer Head Tilt is not desirable.