"To inject something. Usually used in the context of drugs.
My friend booted a bunch of heroin last night."
I guess this might be a possibility. But if memory serves me well (it does so now and then), "booting" is what one does AFTER the first injection of drugs (H).
Thus, one injects and then draws some more blood into the syring/dropper and injects that. Repeatable.
"You still put your cover in your cargo pocket? You boot!"
"We don't care what your drill instructor said!"
2) People with bulimia boot quite often.