Yeshua (Jesus) was nailed to a cross by the Romans as a traitor to the Empire. This was the sacrifice of the God of the Bible for all the evil things he had done. This has showed us the way to sacrifice for our sins.
We must bleed ourselves as a symbolic invocation of the blood of Yeshua on the cross.
On Good Friday, take some incense (preferably sage, although Nag Champa will do), a little water, a clean pocketknife, and go to a place that is sacred to Providence such as the confluence of two rivers. Bless the water and knife with the incense in the name of Yeshua. Then cut yourself on the third inside knuckle (the one closest to the palm) and drip a little blood into the water. Then bless it once more and then spread it on the dirt. This imitates the blood and sweat (water) of Yeshua gushing onto the ground of Calvary as he was nailed to the cross. Make sure to put a bandage on the wound and clean off the knife.