Derek has a feeling the marks that Stiles leaves won't fade for quite some time. It's an instinctual knowledge, that any mark from Stiles will long lasting and meaningful. His lips part, and he lets out a low, pleased moan. His fingernails - blunt, still, human - press against the skin of Stiles' back, leaving red lines across when he drags them down.

Marking, claiming. Being marked, being claimed. His eyes flash red, and he pants.