The muscles around it are tense
That's why it happens
You lie down on your back
On the bed or better the floor
Try to press the small down
Touch toes and arch back
Pull your torso round and out
Digging with your heels
Stretching and twisting
'Til your forhead's on the floor
Scrabbling forward with your hands
Feeling muscles stretch
Otherwise unknown to you
First one way, then the other
You can feel it ready to give way
But it refuses to drop in line
It sits on that cruel edge
With teeth gritted
Tears blinking back
For longer every night
Before it drops away
With a quick-sharp wince
And a shudder of release