John's focus is narrowing to a point that no longer includes the window or anything beyond it — or the mug of hot chocolate, for that matter. He leaves off stroking Martin's belly in favor of simply pulling himself close, slouching a little so he can both curl his arms around Martin and rest his head on Martin's shoulder.

"Mmmhm," he replies, both to Martin's assessment and his question. It's a somewhat generous response to the latter: his back will probably start protesting the current arrangement before too long. But he's comfortable enough for the moment, and he thinks he's struck a good balance of being obnoxiously demonstrative without veering into anything inappropriate. Martin will simply have to put up with him.