This phrase means: to masterbate.

The "snake" is referring to the penis. The word "poison" is referring cum/semen. The phrase can also be said as:

"I need to get the poison of of my snake."
Mike: "I'll be over shortly. I need to release the poison from my snake. It should only be a few minutes."

Jake: Yeah, I think I'll do that too.
by ::MIKESTER:: December 23, 2008
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