Spock is stripped of his logic on an away mission gone bad and turns feral, incredibly violent and utterly brutal. when he comes across Jim, though, he is possessive, protective, and even affectionate.
There's a slick shell over Dean Smith that Sam wants to tear into with his teeth. Rigid control and smooth edges and it all niggles at him, wrong wrong wrong just like the press of Dean's ring finger slipping in next to his other two is so right.