Steve likes it when Bucky is a little rough. The problem is, Bucky's definition of "a little rough" has been skewed by his time with HYDRA. Cue miscommunication causing their sex life to become increasingly more violent, until Steve finds himself in the middle of something he definitely does not want, but doesn't want to stop because he made Bucky agree to it.
+Bucky is definitely not okay with it, but agrees because Steve wants it, and he would do anything to please Steve. +Bucky is uncomfortable by it, but part of him also feels a sick pleasure at not being the one being hurt, for a change. +Steve realizes Bucky has been raped because of the things Bucky says and does during sex. That makes him want to go through with it even more, because if Bucky could handle it, so can he.
Under negotiated kink + HYDRA sexual practices = disaster
+Bucky is definitely not okay with it, but agrees because Steve wants it, and he would do anything to please Steve.
+Bucky is uncomfortable by it, but part of him also feels a sick pleasure at not being the one being hurt, for a change.
+Steve realizes Bucky has been raped because of the things Bucky says and does during sex. That makes him want to go through with it even more, because if Bucky could handle it, so can he.