Steve enters Tony's dreamscape to save him and finds a lot more than he ever expected.
From the kink meme: Tony and Steve ending up in some dreamscape where they can see each other's fantasies as a distraction technique from some villain (I don't care which). Steve opens the door to Tony's dream and sees 3 Steves (I'm not picky which) topping Tony. Up to author how Steve reacts and if this is a established relationship or not.
“I tire of this,” Amora says, and with a casual gesture the entire team is pinned in place, frozen in mid-air. Steve has the unsettling, half-familiar feeling of someone rifling through his head like it’s a card catalogue. A mind-reader as well as a witch, then.
A female voice whispers into his mind’s ear. It’s very tragic in here, dearheart, but I think your armored friend is, somehow, more psychically toxic than even you.
What’s wrong with Tony? Steve thinks, but the presence is gone, leaving his memories of war stirred up like flying insects rising off a lake in at dawn.
The Enchantress opens Tony's mind to anyone and everyone near him. Steve knows he should let Tony keep his secrets, but he's not noble enough to stay away.