Inspired by the prompt above: The Soldier knows only one way of being treated 'in the bedroom'. Sometimes his handlers were gentle, and sometimes they were rough. Didn't matter which; he was trained to show his appreciation by responding with enthusiasm, no matter how much it hurt/made him dissociate.

Cue Steve initiating--or resuming--a relationship with Bucky, unaware of his sexual trauma at HYDRA's hands and, considering Bucky's enthusiasm whenever they have sex (Steve can usually make him come pretty easily, especially when he's a little rougher, the way they used to do it when he was smaller), unaware of the impact it's having on Bucky. Cue Bucky angst and Steve angst once Bucky's feelings come to light.

+++ A sparring to fucking scene
+++++ If they had a relationship back in the 40s that involved a fair amount of rough sex, with Bucky responding with genuine enthusiasm every time Steve makes it hurt/dirty talks to him
++++++++ Bucky trying to power through his discomfort in the present because this is /Steve/ and he used to enjoy this before, so maybe if he tries hard enough he can turn this back into something good
++++++++++++ An under-negotiated rape roleplay that goes off the rails

(DNW: Bucky physically lashing out at Steve when triggered.)