And there's my poblem ... I wish to do all fetishes with D.
Yeah, fucking with E, O, J and - if it has to be - with G (and other side characters) is fun and the only way of getting sexual content in early and middle stages of the game.
But D is the one character the story is all about. She is the hard-to-get-girl. All others - J included - are easy to lay. The corruption part is all about Shirley ehm D

Practicing oral, anal, sharing, gang-bang, zoophilia and what's more if dirty things ... is nice to see E doing it ... but it would be far more better corrupting D that far she'd do it!
For a perfect ending (besides the romantic aspect) D is the ultimately corrupted lover who does all the sexual stuff - in the end going further than E or the other girls would ever do.
The other girls are just keeping players in line who wants sexual content early and tease future events with the one and only marvelous, heart-warming, sugar-sweet, cock-sucking, ass-fuck-loving, golden showering ...oh, I deviated from her innocence :heartcoveredeyes: