I mentioned some of the things that sexually awakened me when I was younger a little while ago. And The Phantom of the Opera was a show* I was obsessed with when I was 14. I think it was the grandness of it, but with Christine calling the Phantom "Master," and lyrics like "I've already imagined our bodies entwining, defenseless and silent" ("The Point of No Return") and of course the below excerpts from the Phantom's first song to Christine, "The Music of the Night" (seduction in song—who can resist? not me), it's no wonder I liked darker, power-exchange dynamics. She completely submits to his every whim (except for the later part of the show). And I apparently identified with that and found it sexy as fuck (despite not using that word as often as I do now, either as a curse or verb).
Hear it, feel it secretly possess you
To be honest, the totality of those two songs are sensual and sexual. I just picked the most obvious lines.
Recently, on my vanilla Tumblr, I saw someone posting list of stories that should not be romanticized. One of which was Phantom of the Opera, and while I know an obsessed murderer does not a good partner make, the musical (and movie musical) have made many women (especially older women call the Phantom "sex on legs")—and while my logical mind knows it's an abusive relationship to say the least (as is Twilight and it's "offspring" Fifty Shades, two other offenders on the list—that I can't seem to find), I still get wet whenever I hear the Phantom singing to Christine (except for the end where he threatens her and all that jazz).
*I'm only talking about the show here, not the book, which is a good read, but much more a murder mystery than a dark love story as the musical makes it out to be