That one is a part of my Peacemaker ‘verse! (Poly Serial Killers)
It will have to be re-worked before I actually post it because I changed details but it’s essentially PWP and Cas retaliating against Dean for the events of What You’re Good For (wherein Dean humiliates Jimmy). Cas gags Dean, canes him, and might choke him (I haven’t decided yet), so generally not good BDSM.
It’s a very… not good ‘verse lol.