Well, see, that is not how consent works, even if the app is supposedly safe, having a character’s body and mind monitored and acted upon without traditional verbal or enthusiastic agreement still removes some autonomy. Especially if the character doesn’t get to express that consent themselves.
See, like I said before, many games sidestep those issues, because however you paint it, it is difficult to justify.
Maybe it helps a little if I explain why this is important. NSFW-Games, most of them, are very flawed and some straight up evil. But it is fun being a little evil as a player and playing out your fantasies with some video-gamecharacter with no true feelings.
But if you start explaining consent this way, you reel them back from their fantasy and explain something indirectly to the player. And most will just ignore it. But we both know that there are impressionable people who will play your game. And while some magic app or the more extreme things happening in other games is not something most will experience... Consent is, that is why you need to becareful with stuff that is grounded close to home.
I hope you can see that I am not trying to scold you here or something like that. To make it short, I think you should not use the word "consent" and instead just explain that the app will only do stuff her subconcious would want. With games like these, just don't try to ground the ethics in stone. By letting them float more, people can make their own thoughts on morality and ethics. The same way most modern shooters don't try to explain the ethics of killing.
This way, you as the developer of this game, distance yourself from those get the wrong conclusions from playing a NSFW-Game. But if you put your own views into the game, you will be linked back to it.
I know this was a long read, hope you can see my point.