Katie definitely wasn't the only nervous one; if he could hear her heart, that she could definitely hear his. Calvin had debated for what felt like hours (but was probably only about five minutes) over whether or not he should wear is shirt to bed. He usually didn't in the summer, but the last thing he wanted to do was pressure Katie into doing anything by setting a tone. It's not like she'd never seen him shirtless - after all, they'd gone swimming before - but in the end Calvin had decided to keep in on. He wanted to Katie to feel as comfortable as possible, and if that meant more clothes, then that's what would happen.
Calvin, too, wasn't exactly sure what was supposed to happen next, and all his long minutes of lying awake thinking about it hadn't seemed to help. It took him a moment, but finally he reached out to her and gently wrapped his arms around her waist in a backwards hug, pulling her over a little so her back was against his chest. There. That was a start.
"So," he returned, nuzzling her neck a little. "Thanks for coming." As soon as he said the words, Calvin kind of wished he hadn't. How awkward would he get? He quickly added, "is everything okay over there? I saw all three of you piled in and it definitely didn't look very comfortable."