double track 

1) Recording two vocal tracks for the same line in a song, making the line sound stronger. Not to be confused with harmonizing. Double tracking is one person recording two tracks to be played together. Harmonizing is two different people each recording the same track to be played together.

2) Putting two songs on the same track on an album. Most popular in the 70s to make an album have only 8 tracks (to fit on an 8-track), but have more than 8 songs.

1) John Lennon loved double tracking.

2) Some of the best examples of double tracking are Foreplay/Long Time on "Boston" and Jack the Stripper/Fairies Wear Boots on Paranoid.

double track by Flannel Flyer May 2, 2005

Double track 

Accidentally snorted two lines of cocaine at once. Derived from railway lines / rail roads / rail track

Oh shit! I just did a double track!

Double track by Hashtagger January 1, 2011

Michigan Moose Track Double Stack

This is a maneuver that requires both a male and female, excluding guy on guy since it will require an unobstructed anus. this however does not exclude girl on girl if a strap-on is readily available. This act starts off with the man(or the man in the relationship) sitting on the toilet facing the tank, and then the reciever mounting the the male. after starting intrecourse the female then procedes to shit which on most occasions will leave a trail of fecal matter on the scrotum.

"man i cant believe that girl did a michigan moose track double stack with me last night, and she wasn't even that drunk either!"

Michigan Moose Track Double Stack by mayor of riley May 6, 2010