Curious why she does this

[Miles&Marvin]

My gal likes to rub her shell against the stiff box wood bushes and was wondering if there is a variable reason known for doing this. See attached. file:///var/mobile/Library/SMS/Attachments/41/01/7BDEEE9E-FA1D-4303-B12C-CEA328579330/IMG_3005.MOV

 

[Yvonne G]

I imagine as the new growth comes in it must be uncomfortable - maybe itchy? or like it's pulling? He does it for relief.