mmm :)! i’d say, without revealing too much, that hyunjin has an inherent comfort with felix’s body that chan doesn’t seem to possess. hyunjin, and felix, are very touchy and affectionate with each other, he’s extremely flirtatious and dishes out many compliments. even before the thing with chan, felix says that hyunjin has seen her naked and also at her worst several times before. hyunjin has a specific way he talks about her, talks to her, touches her and looks at her that is…yeah! compared to chan, who had to be encouraged to pursue her at all, to touch her more, and is generally more held back and hesitant in their friendship.

i think their sexual dynamics (hopefully) reflect their relationships to each other. also, if you just meant top or bottom, well felix doesn’t have a strap or any sort of thing so :3