It's sexual if one or both of you find it sexual. Otherwise, or innately, no. Then again, I wouldn't call grinding your naked crotch against someone else's sexual, if neither person was turned on or thinking about it in a sexual manner...
It shouldn't be unless both parties are hoping for that outcome. All I know is when I hug men I purposely press my tits into their chest because it gets me off so to me that's sexual. It really all depends on the mindset of the parties involved
Yes, it's exciting when hugging some one you like sexually a lot & their breasts press against your chest.