I would love to see a fic where Sherlock notices that John has a habit of always chewing/biting/sucking on something, and they talk about it and John admits that it always comforts him to have something in his mouth, which of course applies to his sex life as well, so Sherlock integrates this into their relationship and maybe makes oral sex a bigger deal, lets John suck his fingers, or gets John some toys that he can suck on, things of that nature. RTYI's welcome!