"Nnnf.." There is always the quick shot of pain when John sinks his fangs in. They are not meant to drink from, so they are larger and sharper than his own.

But after the pain was pleasure. It felt quite nice, but considering he had just come twice, he wasn't about to get it up again. So he just held John and let the warm feeling of being connected to his lover in a different way wash over him.

John also didn't have the anti-coagulants that Sherlock had, so the two little fang marks stopped bleeding a lot quicker than his would.

He was a tiny bit woozy, so he put his hand on John;s shoulder until the feeling passed.

"Feel better, my love?"