User blog comment:TheBlueSlug/Ending/@comment-98.77.232.67-20130728090715/@comment-98.93.230.111-20131209083207

While it would be out of character, let's not forget that Issei is prepared to go to any lengths necessary to help out a friend. It just so happens that this is a sensitive matter as well as a big deal to a member of Issei's harem. That, and If Issei did have lustful thoughts while having sex with Irina, everyone who knows the situation can agree on this:

1) The moment Issei has a lustful thought while having sex with Irina, Heaven's system would kick in, treat Irina as a "natural" Angel and punish her as such. IE: cast out and transformed into a Fallen Angel, if not the first "reincarnated" Fallen Angel.

2) Irina could become devastated as a result of losing her place among Heavens - and by extention Michael's - ranks in the Brave Saint system.

3) Issei will likely feel guilty for causing Irina's situation simply because he couldn't stop being himself for a while for the sake of a close friend.

For these reasons, I believe that Issei can pull it off. Having sex with Irina that is, provided he can keep his focus on the task and his desires in check. Although, should Issei fail and is able to effectively console Irina, there would be a drawback and a silver lining. The silver lining is that should Irina become a Fallen Angel, she wouldn't have to hold her feelings back as much. The drawback that I can think of is..... she would probably need to be tutored in how to "act" like a Fallen Angel. And I use the word "act" loosely mind you.