This is gorgeous: the play of light on Harry's face, the softness of the pencil shading, Harry's winsome expression and beautiful eyes, his crooked spectacles, the set of his mouth with the glow upon it and the slight smile. Snape is almost too beautiful here, his face conveying the faintly troubled surrender to what he wants, the way his closed eye hints at how utterly he cherishes this chance to relax against Harry, his sensual mouth (even if canon says he has thin lips, your version deserves a mouth like this), the extreme character of his nose. The whole picture is permeated with sweetness and a sense of belonging.
And I'm astonished at the way Harry looks directly into the viewer's eyes. He looks truly alive. Fantastic job.