I had someone's back when I was rolling, and they turtled up so I decided to transition to the Truck using the Ford. I removed a back hook, inserted the other one through their legs and locked it off but instead of grabbing the ankle/De Souza control and rolling back into the Truck I decided to fish for the arm first, looking for the Twister. The guy tucked his arm in so I ended up lying across his body, kind of like I was falling off his back but to the opposite side of my lockdown/grapevine. I thought "If I could just reach up and put an s-grip around his head I could tap him from here". And thats when I Twistered myself and popped my own rib.
The only plus side to being the one applying the submission was that as soon as I realised what was happening I could just let go. Now I have a permanent lump on my rib cage and can no longer do the worm without feeling like my ribs are going to pop.
TL / DR - I Twistered myself.