Steve
It's hard to know when Steve is...ya know....(DTF) because he's such a gentleman. But when he is, he usually looks you up & down.
Tony
He will pull faces like this at you, "as a joke", and as much as it makes you giggle, you know what it really means.
Loki
He will just simply give you a huge smile.
Bucky
He will stare until you notice, then he'll bite his lip at you.
Peter
Do I need to explain? The look he gives you is everything, and tells you everything.
Thor
He just stares & stares & stares. But when you catch him he just smiles and looks away.