An unhealthy sensation is when everything is back and swallowed.
Everything is not “back” just as everything is not forward. When we sing lower we feel as if we are in “front” or “forward” which indicates more cordal vibration.
As we ascend the scale there is a feel of moving or stepping back and up, not just back, and certainly not swallowed. This “back and up” feel indicates less cordal vibration.
There is also a feel, as we go into the second floor of the voice, of “turning over” at a certain point both in the range and in vocal development. A true “turn” is a happening accomplished by the vocal muscles when singing upper pitches that also directs the vowel and breath to change. This automatic activity is an allowing. This automatic activity gives us the feel of the sound column being both up and down – up into the back of the head and even a feel of descending into the throat and below.
Note: the feel of the sound column (on higher notes) going down is not the same as swallowed. The feel of “swallowed” is when there is an attempt to make this all happen before the muscles are ready to do it naturally.
Back and swallowed is not a fun feeling as this is a premature overt physicalized and forced attempt to accomplish an advanced vocal reality. The premature attempt results in constriction and rigidity.