[Birkin kisses back with the same ferocity trying to not let it affect him so much. After all, the words themselves were anything but a shock.

He claws at Stein's back, desperately trying to bring him closer. His breath turns ragged as he stretches his other leg out to the side. Birkin leans up, kissing and nipping at Stein's neck, letting out a gratifying moan against throat]