You know you could just replace the tangerine with a cap... call it your 'thinking cap' and put that on every time you get ready to photoread.
It's better if you can visualise, sense or know the back of your head without relying on 'actual physical' items. Imaginary ones are harder to misplace 
The idea is to become aware of the back of your head to get the mind thinking. Much like deciding to wiggle your toe... you have to throw your awareness there first.
Alex
