Sirius' first thought is that Remus' bed is warm- the sort of warm that reminds you of hot baths or fireplaces after being out in the rain. Sirius is cold, and restless, and lonely, and Remus is like a touch of the forbidden, outside world. Sirius wants to hold on and not let go, because he's afraid that if he does let go, he'll forget there's an outside world at all. Remus makes an inquisitive noise in the back of his throat as Sirius' arms knot themselves around his waist, and Sirius leans over and kisses Remus on the shoulder.