Steve:
Steve does his best to pay attention and be respectful, but eventually even he is defeated by boredom. Once he gives in, the two of you play a little hypothetical situation game. One of you imagines a ridiculous Avenger mishap and the other has to guess which Avenger would be responsible.
Bucky:
As you start to get bored you start to doodle on a napkin, then you pass it to Bucky and he'll add something to the doodle. Then he passes it back for you to add on to, and that's how it goes for a while until you end up with the most ridiculous drawing to laugh at.
Pietro:
Pietro will disappear for a few minutes to scout a hideout for the two of you. Once he has found one he'll come back for you and the two of will slip away to the hideout he found. Once you're alone the two of you make the night much more fun ;).
Loki:
Loki has no patience for boring events, he will not waste his time being stuck somewhere he does not want to be. So, when he sees an opportunity to sneak away without being noticed he'll pull you off to the side. Then you both leave before anyone catches you.
Clint:
You will literally spend the entire event figuring out what you will do after it's finally over. Clint will even flip through TV shows on his phone to decide on something to binge when you get home. He'll be on his phone under the table trying not get caught, while you watch out to make sure no one's paying attention to you two.
Thor:
If Thor is at a party or dinner that's fizzled out and gotten boring he will take over. He starts telling humorous stories about some of his escapades and adventures with the Avengers or his friends from Asgard. His stories entertain everyone there.
Tony:
Tony spends the entire event whispering jokes and hilarious references to you and basically entertains himself by making you laugh. Sometimes this leads to you laughing at bad times and getting a bit embarrassed, but at least it's more fun.
Natasha:
Since the public doesn't know about you two, you don't sit together at events. So when you get bored you eventually start to text her from across the room. She's stubborn so she won't respond right away, but eventually she will.
Wanda:
Once you get bored you reach over to Wanda take her hand in yours. Then you start drawing letters on her hand with your index finger, and after that she'll try to respond by doing the same to you. This is hard way to communicate and leads to a lot of misunderstandings, but that is what makes it a funny way to silently communicate.