There's pretty much only combat sex scenes and post-loss scenes, but you can definitely get in-battle scenes and still win. That gets harder as the game goes on, but I'm also playing the hardest mode. If you play on easy it shouldn't require much grinding or anything to proceed and you'll probably still see a good amount of sex by happenstance. Combat scenes happen by enemies succeeding in a grapple move twice before you get a chance to randomly escape their grasp.
If you orgasm, then your character is stunned for a bit and they're free to fuck again or fight you to get your HP down to zero, at which point you are at their mercy until the battle automatically prompts you to give up and get a post-loss scene (which doesn't ever result in game over, you keep your progress and just get sent back to home base).
Also, I've noticed that most enemies in later zones just have more scenes, and often include similar or identical ones to previous enemies' combat scenes amongst the new stuff, so it's hard to totally miss out on any poses. To get all the loss scenes, I think there's just two versions of most of them, one for when you're not too slutty and one for when you're very slutty? Most of what changes is facial expressions though there's one great pose that's locked behind being really slutty and losing at least once, at which point you can start to see that pose in group battles from then on.