In Rogue-lite selecting a position/action is you asking for consent of "hey, I wanna touch your boobs/ass/whatever." It's implied by selecting the option. Then if consent isn't given and you try to force her, then she just slaps you hard, leaves the room and just doesn't talk to MC at all for days.
If your going to add a lot of story dialogue, might as well add some non-verbal lines as well.
Though I don't got a horse in the race, Just figured I toss that out there that there is a consent system in place in Rogue-lite. It's just masked under the action/game mechanic system [if you can call it that] itself.