Sherlock hissed in pain.. he had never had anyone pull his hair. There was an immediate jolt of anger, then his mind caught up half a moment later that this was John.

"Brace yourself." was the only warning that Sherlock gave him. Immediatly, he pulled his fingers out and gripped John's hip. He grabbed himself with his other hand and pushed in, less gently than he had been a moment before, but not too hard or violently.