Rape scenes shouldn't be plesurable for the victim, that sends a bad message and also is not really connected with reality for the vast majority of humans on Earth.
You'd think this would be obvious, and this is coming from one who got raped as a kid... Because IRL Rape most certainly is
not fun!
But in videogames, rape scenes don't really need to be realistic (In my honest opinion). Only a very, very small number of people will be playing a game with 'rape' in it for 'realism'. For most average people, they get off on the themes of 'dominance' and 'submission' (And I would say that this is fairly 'normal'... within the range of human sexuality). People probably are not expected to beat off to the actual beating, the spitting or the mind-fuckery (As well as having a foreign entity up an orifice or two) that ensues in IRL rape (And most of these actions occured to me).
I'm also of the assumption that most people are familiar with the concept that 'IRL' rape is a terrible thing, and whilst perhaps not knowing everything which occurs when it happens, they should certainly know that they are traumatic events with potentially life-altering consequences. So I don't think that rape within VN's or other things need to be realistic (Necessarily), people already ought to know that IRL rape is fucked up. Now, I actually do happen to like it when people go the extra mile and try to make realistic depictions, but those are rare and far between (IIRC, Seeds of Chaos has a pregnant women, who was raped in the past and has 'issues', that really got to me.), and I think people do deserve to have some perspective on the reality, just not in every game or every scene.
That said, what really, really does piss me off is the games or hentai vids where one moment a women is fine... but the very next moment after taking the dick they are suddenly all like "Oh yes, Rape me daddy!"... And I'm like WTF! That shit pisses me off so fucking badly. Most certainly the event that occured to me has fucked with me over the course of my life, but not once have I ever given the thought that I would ever want to be raped again,
ever.
But, before I make people feel squemish or angry at the world in general, I think I will leave with the fact that I'm alive, happy and doing well, and I hope you too are doing well. I'm just here to offer my own output, as one who actually has experience with the 'subject' in question.