For about five seconds, Castiel shuts down in a fit of absolute terror.

-but then he remembers that this is Dean, and it's fine because Dean is everything he's wanted, and Cas has been wanting Dean so badly and he's fine with this. He lets out the breath he'd been holding and, after a moment of hesitation, slides forward in Dean's lap so their bodies are pressed together.

Castiel's lips are against Dean's ear and he's not sure what to do with himself, so he just holds onto the back of the chair and Dean's shoulder and tries not to inadvertently fuck anything up.