He assumes Crowley wants to see him flinch, but beyond a quick intake of breath at the jerk, Castiel barely even blinks. He's uncertain when it comes to sex, it's true, and he genuinely dislikes the idea of giving Crowley any fuel with which to mock him later, but Castiel is a lot more confident now than he was. Even if he doesn't quite know what he's doing, he doesn't want to let Crowley see him be afraid.

His lips do part once Crowley's near enough, but once he realizes there's no kissing to be had, he closes them again. There's a part he needs to play here, and he'll do it.

"That depends on how well you can behave." Reaching up, he curls his fingers around Crowley's hand on his tie.

"Let go."