Wow, quite the Rube Goldberg of kink! I owned a similar vibrator from the sound of it and while I had trouble enjoying those bumps with thrusting, I too found those bumps to be quite enjoyable when set in place (didn't push it to the point of misery tho ;*)

I have often fantasized of being bound and let alone in some compromising position, good on you for giving yourself such a good time! Your writing is very strong (like those batteries! ;*) Please do share the story of the DP!