I've come here today to talk about a widely stigmatized practice in the occult: blood magick. Blood magick is renowned for being 'dark'-and with good reason. In my experience (though it may be pitiful compared to some others) blood magick turns sour. Let me tell you about it.
Two or so months ago, I used a bit of my blood in a ritual. I was way underprepared. I had no idea how finicky blood could be. I only used a little swab of it to mark something. It was a spell to protect a good friend at the time. She had been suffering from depression and an Ed at the time and I felt helpless. I turned to the only thing I could think of-magical means. But I made a crucial mistake. Instead of using both of our blood to balance it out, I used just my blood. Using both people's blood in a blood-related protection spell balances out the protection. Using just ones makes it so that one person bears the brunt of the other person's bad luck, or it just makes your life as bad as theirs pre-protection. I also misphrased the spell. That could have been avoided if I had used different wording, but as I said, I underestimated the power of blood magick. Now, things have been going badly. For a little over a month everyone was doing well, but then things started going badly. This person started getting happier and happier and I slowly got worse and worse. Not only that but because the blood bond was so strong, we couldn't keep a emotionally healthy relationship. I depended on her heavily, but she didn't really care and started ignoring me and focusing all her attention on someone else. But I can't drift away from her because the bond is so strong. The reasons she didn't depend on me was because I had only used my blood, so I was the dependendant. I might bun the object that carried the blood in a ritual to sever the bond, but that doesn't change that the last month has been hell.
In conclusion, if you absolutely have to to use blood magick, do your research well and employ strong protection against psychic vampirism. Always mention in your spell how to reverse it.