Well I would interpret it more as the deodorant would make your armpits feel sexier in comparison to having unshaved armpits (if your a girl), or spraying a deodorant that will cake to your armpits in powder or made it feel sticky or something which would feel gross and not sexy.
Armpits and sexy don't really belong in the same sentence for me though. I mean if the guy had terrible smelly armpits, used a deodorant that was noticeable to see or feel, or he had ingrown hairs or something than that would be really unsexy so in comparison I guess there could be sexy armpits. It's not really a thing though.
Personally I love guys that have really nice hands: shapely and long fingers, not ridiculously small hands or anything but I'm not a fan of huge gorilla man hands. It is one of the first things that I look at in a guy. I also like to watch people do things with their hands for exactly this reason like typing, playing games, fixing anything, driving, you get the idea.
I also like guys tummys. I've never dated anyone super muscular (not fat or even a bit on the chubby side, just not incredibly fit) and most of them have just a bit of tummy. My last boyfriend was really selfconscious about it and it was lovely. I think that has more to do with that really attractive people, well not even really attractive but people who look generic like people in magazines or anything with people that look like what you'd expect naked or shirtless or whatever, it's not like you're really seeing them naked because they're concealed in their own faultlessness, so seeing someone that isn't like that is just so much more intense. Or something.