what was their first kiss like: Liquor laced, when Addison tried to withhold the bottle of vodka from Mark and he crowded her to grab it and then suddenly the vodka wasn’t as important as making out. I imagine there was far too much tongue and a little bit of teeth and afterwards they laughed it off as a random act of college drunkenness that they pretended to forget the next day.
where were they their first time having sex: Empty treatment room in the ER after hours during final year medical school after practicing suturing on each other.
who’s louder: They take turns.
who wakes up first: Addison.
favorite form of foreplay: Drinking. Arguing. Groping in public. Performing surgery.
who performs/receives oral more often: I’m guessing Mark performs more often. Addison was always more of a ‘special occasions’ kind of girl before Mark, and she’s warmed up to the idea but she still doesn’t love it day-to-day. (At least, not mouth-dominant blow jobs. She’ll happily add a bit of tongue to a hand job though.)
what kink they most often use: Addison likes to be tied to her headboard and blindfolded (and Mark likes to oblige). Mark enjoys Addison’s heels digging into his back as she tells him exactly what to do.
who more often tries new things: Mark suggests them, but they’re new things for Addison.
if they had to choose a third+ person to include who would it be: Derek, obviously. Though these days? Possibly Amelia.
favorite toy: I’m having trouble deciding. I see them as a his and hers vibrators kind of couple.
is there a certain thing one of them can’t have sex without: A younger Addison needed to feel like there was some kind of special chemistry or connection in order to have sex she felt was for the right reasons. (I imagine that the first time she slept with Mark was sort of a confrontation in regard to that ideal.) I have a hard time imagining anything that stops Mark Sloan from having sex.
their general feelings on sex in the relationship: It’s the only way they really know how to express their feelings honestly.
how careful are they about using protection: They have a lot of angry sex up against any and all available hard surfaces so I imagine sometimes protection isn’t as important as harder, faster, more. (Also there was that whole accidental pregnancy thing in canon.)
a fantasy of one that the other will never be able/willing to fulfil: Addison’s always wanted to play with the stirrups/speculum/gynae exam scenario. But Mark almost failed his OB/GYN term in medical school and despite extensive non-professional experience, couldn’t perform a decent pelvic exam to save his life. Or at least, not to Addison’s professional standards, and her lectures kind of throw them out of the scene.