A collection of marihuana thats consits of one's own personal stash, and is obtained from a source of known violence, much like a blood diamond. This phrase can only be used within unison of a joint styled form of smoking.
Much more vague varieties can be used for same effect: blood pot, blood tree, blood choad, blood blunt, etc, ...
"Yo! I just rolled this fuckin' joint with some shittly doo da mexican herb! Want some, you butt-plug?" -Anonymous
"Na, I don't want none of your shitty Blood Joint, you shit-headed ass clown." -You