If Rolling Stone and their Gen X readers didn't spend all their time licking Cobain's rotting taint, at least three Nirvana songs would be on that list.
From what I've experienced with women with IUD (like Jauronimo, small sample size), you don't feel the IUD, but the string. I think it's possible for the IUD and string to move down a bit (the strings were just trimmed, right?).