1. Wraith spines are apparently sensitive.
It's not that the information itself is incriminating, John reflects, but it would raise questions as to how he knows about it, which would mean explaining Todd and him in what had to be a small storage cupboard, John's hands dragging down the odd, bony spine, drawing lots of strange sounds from Todd's throat as the wraith backed him up against the wall. The door doesn't come open, no matter how much John thinks at it, and as Todd's leg slides behind his, John stops thinking about anything at all, especially doors shutting themselves on them and effectively trapping them in the closet.
Atlantis has a sick sense of humour, John thinks.
Besides not wanting to explain the touching and the bodies grinding together, and not wanting to reflect on Atlantis' motivations at all, John doesn't see any reason to share this information anyway. Anything that could be used as a weapon against the Wraith, maybe, but he doubts knowing about their spines would do anyone any good.
"Backed into a wall by a hungry Wraith? Don't worry, just rub its spine and it'll be putty in your hands!"
Nope, that will never work.
2. Wraith can purr.
Again, the actual knowledge isn't a secret, but John would rather not explain why he knows it, because he's not that good at lying and there isn't any instance of purring Wraith he can actually tell anyone about. Apparently, Wraith can be really responsive given the right stimulus.
Like when John can't contain his curiosity any longer and his fingers end up tangled in Todd's hair, rubbing small circles on his scalp that seems to really please him. Or when John gets just a little drunk, not sauced but enough to loosen up and let go of his inhibitions, and thinks it would be a very good idea to be in Todd's lap, biting at whatever skin he can get at. Or the before-mentioned incident in the closet, for that matter.
No, John really doesn't want to admit any of them.
Mostly, John doesn't want to admit that lying draped over Todd as the Wraith's body almost vibrates while he purrs steadily is comforting in a way it really shouldn't be, because really, life-sucking space vampire. Never mind the whole DADT, if he admits that, he's going to have to freak out. He'd rather not freak out. That would mean less purring Wraith for him.
3. Wraith are not built for chewing.
OK, so that one, he could share. His motivation for not doing so is brought on by two things. First and foremost, he's pretty sure that on a theoretical level, most people in Atlantis have guessed this already. Wraith teeth are the stuff of nightmares, but they're a lot like shark teeth, designed for ripping and tearing, not for chewing. Considering the Wraith code of conduct seems to be "when in doubt, snarl!" most people already know this. He's not sure if most people look close enough to notice that they don't seem to have molars. John doesn't generally look close enough.
Todd bites, though, and the bite marks have their own tale to tell. This, when he considers it, is another point in favour of not sharing. He spends enough time having to cover the marks as it is.
Besides, he can't help but feeling a bit flustered at the memories any contemplating of Wraith teeth bring up. He felt a bit evil, one day, and ended up feeding Todd some very sticky, chewy toffee, just to see if he could manage to throw the Wraith off for once. He'd been very amused at the resulting snarling, until Todd had decided on a better way to rid himself of the glue-like substance, and John had found himself backed into a wall, his breath stolen away by a deep, caramel-flavoured kiss.
He still can't have caramel without his brain going somewhere else entirely.
Maybe he should change this one to "Wraith taste great with caramel", and have a good reason not to share it.
4. Wraith are slippery when wet.
Todd's skin really isn't as oily as it looks, just cool and oddly smooth. It's nothing like human skin at all. Wraith are not strictly speaking cold-blooded, they can regulate their body temperature and they generate their own heat, but their bodies are colder than humans and their skin feels closer to that of a frog than anything else.
The first time he has an opportunity to do so, John spends what seems like hours mapping Todd' skin, tracing tattoos and deciding that while Wraith skin is plain weird, it feels decidedly nice to touch. Todd seems to really like the touching, too, which is definitely a bonus.
But then John bribes the guards to leave them alone for a while, and Rodney to disconnect any surveillance there might be, and drags Todd to the showers with him, and learns two very interesting things.
For one thing, Todd does actually clean his hair; he just seems to have an irrational hatred for hairbrushes and leaves it to dry without any care. That explains why it keeps getting messier, but doesn't actually seem dirty.
Secondly, and more importantly, water makes Wraith skin slick. Very slick. It's probably some sort of very interesting adaptation to humid environments or something, from a biological standpoint, but John can't think about that when he has his arms full of wet Wraith, Todd rumbling against him in amusement, or arousal, or both.
Probably both, John decides silently, because Todd is always amused at his expense, but then Todd slides slick hands down his body and he gets other things to think about.
Stupid wet Wraith and his clever hands.
5. Wraith can sing.
They're in a hole somewhere, and Todd's leg is broken. It's healing, of course, but not as fast as it would have had he been feeding recently. Even when it heals, it won't change much, because the hole, which is technically an abandoned mine shaft, is too deep even for a Wraith to jump out of, and the walls of the shaft are old and crumbling. Climbing is not a good idea.
John has hit his head, and he's bleeding a lot, like head-wounds are prone to. That alone doesn't worry him, but Todd looks at him and tells him his pupils are uneven, and that really isn't a good sign, so John carefully sits next to Todd and tries not to move too much.
It's not too bad, at first. They have plenty of water and John has some energy bars, and though Todd hasn't fed recently, he still has days, if not weeks, before hunger becomes a problem.
Trusting a Wraith does not come easy, but John does trust Todd not to feed on him simply because he can. Maybe eventually, he will learn to entirely trust Todd with his life. He just doesn't think he can trust Todd with the others' lives.
But time passes in their hole, and John is getting dizzy and a little nauseous. He doesn't like that. The radio has been destroyed, or maybe just displaced, and they have no way to connect the others.
John knows they will find them. Rodney will think of something. He always does. The rest of his team will help by insisting on his retrieval. He just hopes they find them before he gets worse.
Staying upright is uncomfortable, and he gradually slips further down, until his head is on Todd's shoulder. He considers jerking away, but just the thought of sudden movement makes him hurt, and the Wraith doesn't really seem to mind.
Todd's shoulder does not make for a comfortable pillow, bony under whatever it is his coat is made from, but John still finds himself slipping into a sleepy haze. Maybe it's the simply the head wound, or maybe it's the almost soothing rise and fall of the Wraith's chest. Todd breathes slower than a human, slower and softer, yet deeper at the same time. It could almost be hypnotic if John let it.
He lifts his head instead; carefully not groaning at the pain it causes, and looks up at Todd. The Wraith seems eerily calm, as though he is halfway into hibernation, but he shifts and looks down at John, almost questioning. He lifts his hand and carefully touches John's injured scalp, fingers coming away bloody.
John asks him, then, to wake him after a little while should he fall asleep. He can never remember if head trauma means staying awake or if sleeping is all right, but he knows that when he fell out of a tree as a child and hit his head, he had been sent home with instructions to wake him every hour or so for a while. Todd doesn't reply in words, but the sound he makes sounds like agreement to John, and he twists so that when John slowly, almost tentatively rests his head on Todd's shoulder again, they are both in a more comfortable position.
As he half drifts off again, Todd's hand comes up to his neck, resting gently on the skin there. John doesn't know if it's the injury or a sign he is getting too used to the Wraith's presence that he doesn't flinch.
When he first hears the sounds Todd is making, he can't make sense of them at all, but then the fingers on his neck start tracing patterns and John realises that there is more than the sounds he can hear.
Todd is singing to him. Only half of it is the sounds he hears. The words, if they are words at all, blend perfectly with the harmonics that spill into his brain, resonating throughout his body. It's unlike any song John has ever heard before, both beautiful and unsettling at the same time. Even aching as he does, mind fuzzy and dull, John knows that this is not something that a Wraith would usually share with an outsider. He closes his eyes and leans his full weight on Todd, willing himself to stop thinking for a while and just listen with all his senses.
He loses track of how long he lies like that, pressed against Todd and feeling him sing to him. The Wraith's fingers are cool where they brush his neck and his odd, resonating song running through both their bodies in unison, synchronised in a way that should scare John witless. It doesn't, and that is somehow even scarier, but the Wraith song seems to soothe it all away.
The sound of voices break the spell, and Todd's song fades away to nothing, though it still resonates within John's mind for a while still.
Before long, his team arrives, with ropes and harnesses. They are not happy to see Todd there, but they stay professional about it. Todd's leg must have healed, because he helps John into the harness, then climbs out with all the grace of the apex predator he is. He offers to help get John out of the hole, of course, but Ronon growls at him. Todd gives that strange sound John has classified as amusement and walks away.
He offers no farewells, but none is needed, because there is still echoes in John's mind.
The echoes has faded, later, when John is back in his room on Atlantis, lying back on his bed with memories of a song like none other running in his head. It never comes close to the true version, though. It's nothing but a pale imitation.
This, John could share. He could, but he doesn't want to. Todd had shared something with him he was sure no non-Wraith had seen before, and he wants to keep it between the two of them. A secret between two who could be brothers were circumstances different, a song John will remember forever but never be able to replicate. Maybe he will come to curse Todd for once again reminding him that there are nuances to what the Wraith are, but he will deal with that if the time comes.
For now, he is left with a secret he will never share, and a shadow of a song that will linger in his mind for a very long time.