I have two questions

Chapter 28 is the first chapter with new content compared to the anime. The reason its called smut is because they do show a bit of nipples, however that's only in the earlier chapters. After that, there really isn't any smutty content. I think it was originally going to be a lot more smutty, as the author tends to have more sexual content, as they generally write smutty one-shots. So if you're not into smut, don't worry. The most you'll see is a set of nipples in an earlier chapter with Aoi.