The narration is not honestly certain Gabriel would notice. It might be noted at this point that, in the rare moments when he's not directly occupied with Spots and allows his mind to wander, Gabriel's face showcases a milder, more subdued version of Angelo's own just-got-laid grin. If one were forced to put a name to this grin, one might term it the just-made-out-with-a-boy-repeatedly-and-still-slightly-terrified-one-is-going-to-go-to-hell-for-the-indiscretion grin. (It's good that one is not so forced, really, or one would have to be ashamed of one's lengthy nomenclature.)