This one was prompted by a post on 74flawsasofyesterday's tumblr. I couldn't link it here, but it is a gifset from when Castle makes the elevator door close during the 2nd season episode 'The Double Down.'
"Why'd you do that?"
"Do what?" Castle replies all too innocently.
"Make the doors shut before Esposito and Ryan could get on the elevator."
He turns to face her fully and steps to her, bringing their bodies flush. He reaches up and takes a hold of her face gently.
Then he kisses her.
The kiss is not frantic, there is no hurry in his touch. He simply lavishes her lips with his own, slowly, passionately. Her eyes slip shut and she moans under him, but doesn't move to deepen the kiss. Suddenly and all too soon, he pulls away. The bell dings, announcing that they have arrived at the first floor.
"That's why I did that," he smirks and lifts his eyebrows. "I hope you don't mind."
"No, I don't mind at all."
"Good," he nods and starts to walk off the elevator.
"Castle, wait."
He stops and looks over his shoulder at her. "What?"
"I think I left something up at my desk," she presses the door close button. "We should go back up just to check," she says with a wink as she steps back over to him.