You chose the perfect title to get my attention.
I started thinking of something before I even opened the thread so I hope you like the dare. Though I understand your reasons for not going through with the below.
Chew a lot of gum and stick the plectrum to the bottom of your butt plug. Use enough to cover the bottom and bottom sides of the butt plug, and enough to make sure the plectrum is stuck straight down on the bottom of the butt plug. Then let the gum harden over time by placing it in a cold location (outdoors/ refrigerator). Once hardened and checking if the gum is strong enough to keep the plectrum in place, insert the butt plug and squat with the guitar between your legs. Perhaps place the guitar on an elevated place? And enjoy shaking your ass side to side while holding an accord.