The "excuse for the male lead to have tons of sex" (read: plot) seems viable enough: "You must look for a sakura petal on a woman's neck. And it'll only activate when she reaches an orgasm." ...okay. So Shinji ends playing a role whilst wooing a chick and (gentlemanly, as oppose to what Rance would do) win his way into her heart before he wins his way past her panties. But then there's Sae who swore to do it with him when they get married... I'd choose that hot chick Zero if I was him, but hey. He has a job to do. ;)