I adore the little details of this one that flesh out the whole to make it such a realistic depiction. Severus' wrinkled forehead, which suggests to me his brows are raised in bliss at the scent of Harry; how Harry’s shoulders are hunched, his neck an arc and his spine bowed, so that I know he is boneless with pleasure; and then that Severus is about to suckle at Harry’s throat when a nipple is hard and wanting. As soon as I saw this, I knew it was about making love, not sex, which is why it makes my heart sigh.