The same as shakin' in my boots, which means scared. The phrase is used sarcastically often.

The specific term comes from Austin Powers in which Dr. Evil says "I'm shaking in my little space boots", although some falsely attribute it to Toy Story. Also, the "little" is commonly skipped from the phrase.
Thug: "We comin to get chuuuuu"

Girl: "Oh mann i'm shaking in my space boots"
by blaqq September 20, 2011
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