From mothensidhe on Tumblr :
"This can be an effective way to charge ones magickal tools. It is important to note, however, that charging tools in this way can sometimes affect the way the tool works for other people, so if you choose to do this to a tool of some kind, one should avoid then giving it to someone outside their bloodline later on without cleansing it first. This tool should not be shared, in the meantime.
Ive used this on my athame and tarot deck(s) before. (The latter I may not recommend, because I did somehow slightly damage my second deck in the process). This is also very useful when making charms. What this does is imbue your personal energy into the object.
To christen a tool with your own blood, draw blood from your thumb or index finger in your dominant hand and press it to a certain place on the object, itself. As you do so, focus on the heartbeat in your fingertip, pressed against the surface. Feel its steady rhythm and feel your essence seep into your tool. Envision your tool drinking it in and taking on your attributes. It is to become an extension of yourself from now on."
I use this with my athames and wands. For me, blood christening is an incredibly powerful way to connect your witchy tools to yourself. I don't think any substance can get much more powerful than blood. Please remember though, safety first. Blood carries a ton of nasty diseases. (like aids. you don't want aids.) I personally wash the blood off of my tools once I feel like the item has "bonded" enough with me, although some people do keep the blood on the item.