Directed masturbation exercise

I’ve tried this exercise a few times now, and each time my arousal level is non-existent.
Not 100% sure why but I’m pretty sure it’s being told what to do to myself by a man’s voice, I find it to be a big enough turn off that I am unable to enjoy myself at all. Wondering if anyone else has had similar issues or does it just take a while to see results using this exercise?