The reason Erosblog doesn’t cover more mooning stories is that available photography usually features normal guys with semi-hairy butts — not a particular erotic trigger for your humble reporter, nor indeed, so far as I know, for any appreciable and identifiable fraction of the blog readership. However, I must admit that the Moon Amtrak website features one nice side view of a well-turned female bottom:

Thanks to Functional Ambivalent for the link.