Anus is a very erogenous in both sexes. in fact, in the women's case, when it's well done they prefer penetration in their anus to their vagina because there're more nerves endings in the first, many of them from their own vagina. Well done means softly instead violently (in women this area is extremely sensitive), as it's must be in men too. If this can help
http://www.ayushveda.com/mens-magazi...e-and-dislike/