On the hunt for Bucky, while Steve is busy with Ultron, Sam runs into Rumlow who is also looking for Bucky, and they get sex pollen'd together. Violent, bitey horrible hatesex ensues. Anon does not care who does what.
+Rumlow telling Sam what Hydra used to do to Bucky while they're fucking and Sam hating it but getting off anyway
++Bucky hears or otherwise knows what happens, assumes it was either consensual or as fucked up as what happened to him, and the aftermath trash