It made him laugh how Tony was almost surprised he was there, that he could be so absorbed in something. But Steve got the same way sometimes when he was drawing something, like he was somewhere else in mind even if he was present in body. At least Tony came back down to earth as he kissed him and Steve figured he was onto a good thing and kissed him again down toward the collar of his shirt.
Maybe some people would be annoyed, or insulted that their someone could forget about them, but Steve didn't see it like that. He loved how passionate Tony was and he benefited from that passion very regularly, thank you very much. If Steve had needed him then he'd have asked, he didn't need Tony to hover over him to feel cared for.
"It's time to come up for air, it's dark out," Steve said as he gave his hips a squeeze. One hand came up under his shirt, resting over his chest and reactor as he held him for a long moment. There had been a lot on his mind lately, mainly how much he loved him, a few nerves and it all seemed easier with Tony in his arms.