A space donkey is a person who refues to get off drugs. He/ she's so hooked on the high and that outer space feeling that they refuse to get off it.
That guy has been on heroin so long, he's just a donkey about getting off it. He's a Space Donkey Bru!
by Definition March 16, 2005
When you take a shit into someone's vagina.
That girl was sick. She asked for a space donkey.
by Chris Mammarelli August 24, 2005
The act of defecating into a vagina.
That Sophie girl is sick. She asked Rob for a space donkey.
by K-Blo September 09, 2007