body — what is their favorite body part of theirs? of their partner(s)'? are there any specific body parts they like to pay special attention to (ex. feet, hands, ass, etc)? where are their erogenous zones? where are they most sensitive?
music — do they like to play music while having sex? what kind of music? is the music for vibes, aesthetic, or simply to drown out the sounds they and their partner(s) make (or even a mix of all three)?
oh, that one is easy on his end because it's his eyes. they stay the same no matter what. come today, tomorrow or a whole new life, and he will look up to see the very same eyes that he saw the first time he gained a proper state of begin. that orange tint, that warmth and that slight eeriness to them... in the end, that's him. the truest fragment of that myth that never quite holds an actual form.
when it comes to his lover, it's... eyes, as well, because he can read so much of them through glances. even as they smile, eyes give off the other's true emotions and intentions, and he does so enjoy witnessing his partner in the moment. he loves seeing the way their eyes light up in joy over something or how they grow warm alongside a deep laugh that they don't quite want to submit too. he enjoys the darker aspect, too, when his partner struggles to look at him for their own reasons, or how they grow a little heavy at times. it's not sexual, far from it, but it's intimate to him to be able to look someone in the eye and actually see what they have to offer of themselves.
should we talk in more sexual terms then... gallagher is very much a fand of lips. those are nice, always, because they move so neatly. they bring a smile, they reveal laughter and there is something very enticing in how his partner's lips part with light breaths, even more if he catches that breath against his own throughuot a kiss.
as for sensitive zones... i don't think it's about a particular zone with gallagher, but more about the person he is with. anything can be become erogenous to him if his lover is having a good time and running their hands as they please. it's the intention of it all. them wanting to explore him on their own terms, effortlessly. in some cases that might be feeling a lover's hand grazing his chest or to feel their weight against his body one way or another... such as leaning into him during a kiss.
when it comes to music, i can't say that isn't opposed to it but he doesn't really set the mood with music. he's such a talkative man that he'll keep a conversation alive for far too long for someone to pick up on music around them, but should there be music then it'd have to be something tied to jazz (possibly a little on the saxophone-y side of things as he likes the tones). it's not a must though, because he'd much rather be in the moment with his lover and pick up on possible cues as breaths or sounds. the music would mostly be there for the whimsy of it all, or a woops forgot to turn that off. he can enjoy some music in the background whilst making out though, of course, because it could be tied in with dancing...