HEADCANON

When Steve and Bucky were kids, whenever Steve was sick Bucky would sleep over. He would often wake up at night to Steve coughing and wheezing, panicked and  unable to breathe. So he’d go and hold Steve and whisper calming things in his ear, telling Steve to relax, that he’d make it okay, telling Steve to feel him breathing and breathe.

Present day, whenever Bucky wakes up from a nightmare screaming, terrified and unable to breathe because his chest feels like it’s constricting for fear, Steve rushes in and holds him, whispering calming things in his ear, telling Bucky to relax, that he’d make it okay, telling Bucky to feel him breathing and breathe.

Headcanon that Bucky has a Captain America plush toy which he calls Stevie and talks to when nobody’s around and sleeps with at night. He keeps Stevie hidden under his pillow and thinks he’s kept Stevie a well hidden secret from everyone, including Steve, but all of the Avengers know.