i loved your magnus + shoulder movement gifset! i'm curious, why do you think he does it? x
*rolls up sleeves* *cracks knuckles* ok let’s do this
i think he does it for multiple reasons, all depending on the specific situation. a lot of the time, he does it when he’s being flirtatious, aka mostly around alec.
first of all, i think it’s because he’s essentially a cat in human form; he’s effortlessly graceful and he uses his body language to appeal to people, to either indicate interest (as in the case with alec) or to indicate his power (see below).
his cat-like, very smooth movements indicate an ease about him, a comfort in himself that i think a lot of people find attractive. while other men usually stand still to show confidence (think soldiers, or jace and alec’s more stiff postures), magnus instead uses more fluid ways of movement that are usually coded as more feminine, and this makes people watching him ascribe him other qualities that are typically coded as feminine: soft, gentle, vulnerable, etc. i think he likes to play these qualities a lot when he’s flirting (see “i’m not being cryptic, i’m being coy”), combined with an unashamed (read: masculine) habit of making innuendos, preferably together with a name drop.
as we know from his dashing wardrobe and love of makeup, magnus doesn’t shy away from breaking gender stereotypes, and i think his body language show this a lot, too. he happily mixes feminine and masculinely coded ways of movement, and plays with the different expectations people put on him based on these ways of carrying himself. i think this is also closely tied to how comfortable he is with his bisexuality. bisexuality, like androgyny, is everything and neither, and i think magnus through the years has become more comfortable with the fact that he is just that: everything and nothing.
personally i can relate to the feeling of freedom in your physical expression once you’ve come to terms with, and embraced, the fact that you’re not “normal”, in this case straight. magnus knows he’s not straight, he knows he’s never going to fit into any boxes people try to shove him into, and this gives him a freedom to explore his way of expressing himself without being limited to what he should be doing or how he should move, based on societal expectations. he can embrace traits that are coded as feminine or masculine, he can combine them, and he can do this without shame.
however, and this is where it gets really interesting imo, he doesn’t reserve these shoulder shimmies only for situations where he wants to appear softer, more approachable, etc. he also uses this relaxed set of movements to establish dominance and confidence, not only in himself as a romantic interest when he’s flirting, but in himself as a danger to others, and in his own abilities.
in the scene at pandemonium he does that slow shoulder shimmy that otherwise would be coded feminine, but this combined with the way he’s holding himself very tall, his chin high and his cat eyes showing, leads us (and his opponents) to believe that he’s so powerful, so in control of the situation, that he can almost laugh about it, that’s how at ease he is. he’s so calm, so secure in his dominance of the situation, he doesn’t have to use the traditionally masculine variation of dominance (as the circle dudes do, standing very still, almost like soliders. again, think jace and alec) to show that he’s the one in charge. and what’s so important is that he’s not establishing his dominance in spite of also carrying himself in a more femininely coded way; his presence as a dominant force is undoubtedly because of the traits assigned to him by his usage of these femininely coded movements.
if he’d stood up straight (lol) and still, while delivering the same lines, the interpretation wouldn’t have been the same. sure, he could’ve still been seen as confident and dangerous, but there wouldn’t be the added element of effortless confidence that, in my opinion, makes him a much more dangerous enemy. a person that seems to think so highly of themselves that they don’t think you pose any threat and therefore won’t even bother trying to intimidate you (because who would use femininely coded movements and qualities to intimidate someone??? bc feminine people are weak right?), now that’s scary.
therefore, the feminine part of his expression is key to the threat he poses. he’s establishing this physical dominance, not by soldiering forward and punching them in the face, but by partly using femininely coded body language and instead relying on their fear of his abilities, which i think is really cool.