I have no idea what's happening on her dress -- a hug, maybe? -- but I don't even care. The leather cape and the swagger with which she's wearing it feels delightfully badass to me, as if she's just landed at this Avengers: Endgame press conference to give it a welcome jolt of estrogen and save Robert Downey Jr. from himself.
Of course, it might not be working:

Yep, still shenaniganizing.

Is he dancing? Itching uncontrollably? Trying to kill a suspicious insect? Only he knows. Well, and possibly everyone in attendance, but I wouldn't guarantee it. It's often like he has decided he's the Robin Williams of the Marvel universe.

RDJ: ACK!!! YOU GOT ME!!!
Jeremy Renner: I'm also here.
Brie: I'm the future. Bye boys.