to take a girl on and try to hook up your friend with her friend
"Yo we tried to double up, but yo dumb self wouldn't come."
To have sex with someone who is twice your age.
If you are 20 years old and have sex with someone who is 40 years old, you have successfully done a double up.
If you buy 40 dollars worth of crack for 20 dollars and sell it for 40 dollars you just pulled a double up.
Ay main let me get a double up up off you.
Run, Take off, Speed away. Break out.
"Double-up, the Elroy comin'."