I know the song 'Sex; isn't by Tokio Hotel, but I heard that they did a cover of this song. I liked how they sang it, so I thought why not lol. Thanks for the heads up though ^_^
I left it open for the reader to decide, really. If you want it to be Gustav, then it's Gustav. Some people see Tom as the narrator; others, someone else entirely. But I can see Gustav, definitely. I hadn't really thought about it though...