Lyric discussion by notyourkhakis7 

Cover art for Down lyrics by Stone Temple Pilots

I think the song is about sex as are a good number of STP's songs. "I've been waiting for my Sunday girl," has anyone ever heard the following expression? I'd do her six ways from Sunday. This is clearly what Weiland means when refering to his Sunday girl. The song is about waiting a long time to meet that one girl that will turn your world upside down.