Is David Bowie a top or a bottom?

http://www.youtube.com/watch?v=s2L4hL2IvUk makes me think he's a power bottom, as evidenced by the line 'got laid by a young bordello', indicating that he's a bottom, but 'that was vaguely half asleep' should imply that Bowie was doing all the work. Is there any concrete evidence on this subject?