The archer could see from his little perch in the lab that Bruce wasn't having a good day. Tony was fucking off fighting with Steve and nothing was really getting accomplished. So naturally Clint hatched an idea that involved a stack of papers, a pen, and a bit of folding.
Clint hand writing was like chicken scratch and he knew it so the first on he did was a crude drawing, that makes everyone happy right? He folded the piece of paper into a little plane and threw over to Bruce landing in in his curly brown hair.
Bruce pulled it out of his hair and opened it; he looked around grimacing until he locked eyes with Clint. He balled up the paper and though it in the trash with a huff. So as luck would have it, not everyone liked sexual stick figure drawings.
So Clint tried again but this time it was a little note that read "You look really good in that lab coat, Freckles." This time he threw it and landed it right in front of him. A small smile lit up Bruce's face as he read it folding it and placing in his lab coat pocket. Clint must have sent about a hundred of those little note ranging from "Let's play doctor" to "I bet they won't even notice If I came down there and bent you over."
He was down to his last sheet of paper and he knew he had to make this one count. So he wrote three little words that he knew would mean just as much to freckles as it did to him. "I love you" When Bruce got it he was all smiles he wrote something down on the paper and threw the plane right back. "I love you, too"