Sherlock fell deeper and deeper, he was going to go over the edge, John's mouth and tongue were so terribly talented, but he didn't want to come this fast, like a horny teenager.

He put his hand on John's shoulder and pressed a bit, making a noise that sounded a bit like "Shtaaahpp.." He groaned and tried to wriggle away. He was close.. right on the cusp of coming.