Although music and pickup are both arts with similarities all over the damn place, in my opinion using music to do anything other than just expressing yourself fully for the sake of expressing yourself fully is called one of two things (or both):
1. "Being a tool"
2. "Selling out"
I'm a musician, too. I started learning how to play guitar 6 years ago. Why? I thought it would get girls to give me attention/external validation. The fact that that was the reason I started playing guitar disgusts me. It really makes me sick to my stomach. I think I know how prostitutes feel. This is also why I hate "emo," because it whores music out in a desperate cry begging to be validated by an external source.
Music to me is sacred. It's supposed to be a pure and skilled expression of how you truly feel, so it's an extremely personal experience every time you throw some notes together. That's why it turns girls on in the first place, anyway... because you're showing true confidence in sharing how you really feel without an ulterior motive. It's just pure and natural YOU.
The very idea of using music that you poured your heart into for an ulterior motive makes me feel like someone is defiling a holy relic or some shit. Don't dehumanize yourself by devaluing your true expressions of who you are. Your music represents how YOU feel; it isn't about making girls horny and wet. The motive for music is self-expression. That's it.
So, if you want her to hear the song, don't make it part of some plan. However it ends up getting to her ears, let her hear the song just for the sake of expressing how you feel while expecting ABSOLUTELY NOTHING in return. That's musicianship.
That's just my radical "mixing-music-and-pickup-is-morally-wrong" stance on the issue, anyway

Take it or leave it...