As it says on the tin - This mod adds nipples to the game, nothing more, nothing less. No modified outfits, no unnecessary nudity. Just nipples. They will show from behind clothes, from under pasties. When you break clothes (will need to grab the uncensor mod however!) I added nipple bumps to Ayame's portrait and areola to Murakumo's portrait (because they'd be showing if she had nipples)
As far as I know this should effect every girl in the game, there's 10 different textures for 5 different skin tones, although I have only gone through Gessen academy, they've shown up on the girls from other academies I've seen as well (Homura's textures almost slipped past my radar somehow, but I got them as well hopefully!)
Let me know if it bugs out for you or anything. I am using a pirated copy of the game(I haven't bought it yet, I plan to soon) if that messes with texture IDs from uMod (which you'll need to use btw!) Download is in the attachments!