User blog comment:B214/Question and Answers 6/@comment-24098614-20161119184223/@comment-29963364-20161121072904

I'm just saying that out of all the girls, Asia has the best relationship with most of the other girls in the harem, and she's the most accepting of Issei's perverted tendancies (as long as she's involved since she doesn't want to be "left out/behind").

So as long as Issei pays attention to her and shows her plenty of love, she's fine with sharing the experience with the other girls.

So Asia isn't the most perverted (that title goes to Akeno and/or Kuroka), she's the girl with the biggest, kindest, purest heart.