Bucky is you're boyfriend and nat is you're "friend" that tries to steal him from you.

You're having a sleepover with nat but you invited bucky too so you sleep more comfortably. Bucky is laying in bed between you and nat. You're laying against his side while nat was laying next to bucky, she turns her head after a few secondes and touches buckys hair.

Natasha: "you're hair looks really nice. Like... really nice."