For

Jack/Daniel and John/Rodney, 650 words, R
1. When John was first stationed in Antarctica, he thought he was allergic to something there. Just a little. Maybe the detergent they use on the sheets or something, because his skin kind of... itched, all over. Well, not really an itch. Tingled? No. Closer to an itch, except that it didn't make him want to scratch. He wanted to do... well, he wasn't sure. Anyway, it wasn't really as bad as all that, subtle enough that he totally forgot about it most of the time, until he sat in the chair and it suddenly went away. He never found out that Jack had felt the same way, between the first time he stepped into the presence of a Stargate and the first time he stepped through.
2. Pilots tend to be careful of their eyes, and understand the problems of glare and the need for protection very well; it was perfectly normal for both Jack and John to always carry sunglasses. Sure, they seemed to be a bit obsessive about it, but everyone figured they were a concession to vanity, or maybe a statement of cool. Given that John is always dealing with a glare off the ocean in Atlantis, and Jack never knew what level of UV he was stepping into on the other side of the gate (the MALP gives a number, sure, but you don't really know), their mutual sunglasses fetish is practical enough to not occasion comment. To this day, no one has figured out that the Ancient gene is generally associated with a slight oversensitivity to light.
3. Rodney can't prove a thing, but after digging through Jack O'Neill's records (don't tell anyone), he is convinced that the Ancient gene predisposes a carrier to bad hairstyle decisions. Between John's finger-in-a-socket look and that mullet? Seriously. Jack won't admit to the mullet, by the way. He grew it mostly to have something to cut off when he joined up, and an overtly symbolic and sentimental gesture like that is the kind of thing Daniel would never let him live down.
4. Neither Jack not John ever got chicken pox, despite their mothers waging a dedicated campaign of sending them to play with every pox-stricken kid in their schools. They were both vaguely aware that they were at risk and ought to avoid it like the plague during their adult lives (at least, until Janet gave Jack the vaccine despite his bitching. John objected to Carson's attempt, and Rodney's smirking accusations of voodoo didn't help. Keller doesn't have the guts to force the issue), but the truth is, they needn't have worried.
5. Daniel knows that Jack responds to touch in some slightly odd ways. Light licks and kisses and touches on the backs of his thighs don't do much for him, but good hard squeezing and biting, and even impact (oh God, did Daniel enjoy finding that out) send him into ecstasy. His knees and kneecaps aren't ticklish like most people's are, but the tendons around his ankles are. The acupressure points at the base of his spine get especially good results, but his nipples are completely unresponsive. And those little hollows below his shoulder blades? Make him shudder and jerk the way Daniel does when someone works on his neck. None of those things are too weird, all perfectly within the normal range of variation of human sexuality, the sort of quirks a lover slowly maps and discovers and learns to play like a pro, so Daniel never really thought anything of it.
John shares some of the same quirks, and some closely related ones. Rodney doesn’t know them all yet, but given the intense scientific hyperfocus he's dedicating to learning John's body inside and out, he's going to make up for the years Daniel has on him pretty quickly. But the chance of them ever comparing lists is pretty slim, and it would take a lot of focused testing to sort out the actual quirks from the subtle genetic influences, so nothing will probably come of it.
Random side question: I am starting to see movement on various fandom Christmas/holiday exchanges, including the poll post at

