I don’t really remember much of this anime

I need help to find a anime that I saw either in 2016 or 2017 on YouTube and I remember it seeing a girl with either with long blue hair or long purple hair and the first scene was she dreams of having sex with a boy that she loves and I don't remember the rest but I do remember another scene that she was sneaking into the room that the boy she loves and sees a bulge in the blanket and she pulls it back and to see a Tameshigiri Tatami Cutting Mat I think it is or not