I think he should be standing on the pin prick mat, any movement to relieve the discomfort added to the vibrator, knowing the coin drop would mean cock pain, should mess with his focus. Depends what's happening above the bits we can see. I should like his arms to be tied above him leaving his pits and sides open to tickling as well. 

As for the crime- I can only think he messed with the plastic bag containing the key and tried to jerk off. Definitely needs punishment.