A tradition children do in my area which includes blood. And I mix it with magic. I feel so smart and pretty and witty...
Jokes aside, it is really true. There is a tradition children do called "Being Blood Brothers" I do not know it is also in world, as I have never heard of it.
This tradition is, 2 people cut their somewhere in their hand. And they touch the bleeding area together, and this friendship is very, very strong that goes for years, maybe to grave, thats why not a lot of people don't do it.
Since magic is about observation, I wanted to bring magic into this not safe practice. A spell, nah, a very simple ritual, action, etc...
2 people who are together, maybe married, and practice magic together might see some use in this thing.
Atleast 2 cadles are lit. If you can, light seven. five for elements to come to the circle. You want all universe to witness this event. Or you might just use symbolizm to call elements. The rest of the candles must be used for your patron deities. For yours and your partners.
The blood is something that carries a great deal amount of magic energy, because it carries life energy along with it. (Just like "a special type" of magic I'm afraid to say the name of...)
After this, cut the head of your fingers, or side of your hand, just a little bit. Put that cleaver back. (Okay. D:) Sit in the middle of the circle/candles and make the cuts. After that, took a deep breath and put the bleeding parts together. Chant the following, together.
"Universe, life and mother earth, witness this bond, and allow it to be heard. Blood mixed, magic connected. Never make broken this bond."
After this. hold the bleeding parts together a little bit more. Now bandage it up. (take them to circle with you.) Because they will relieve pain of the cut. Now you can meditate together without pain to distract you. Meditate together. Imagine your magical energies now working together "WHEN TOGETHER" so you can still do spells alone without anyother energies. And becoming more effective to accomplish the selected goal. (Yay!)
You are now blood-bonded this person. Together you magic is very powerful. But if one dies. The other dies too.
This... Thing might get some bad reviews. But I wanted to share it for the ones who might find it useful.