On the double comes from the term "double time". When marching if you double time you are running. So on the double basically means hurry up.
Double verticle lines surrounding an expression means to take the absolute value of the expression. The absolute value of an expression is the expression if it is positive, and the negative of the expression if it is negative, i.e. the unsigned distance from zero. Analytically, in order to process the expression, the absolute value of an expression is also the square root of the square of the expression.
To get the "Come Back to my Place" expression you need to buy the expression book from the Bowerstone Market bookstore "Fiction Burns."
Yes, I believe the French expression for this is double entendre.
ghosts
From the movie "clueless"
To use the "Come Back to my Place" expression, you must target the person of your choosing and open your expression menu. Then go to the "Flirt" section and choose "Come Back to my Place" expression.
Expression is the key to making music come alive. It is the heartbeat of music.
The expression "name your poison" means What will you have? when offering a choice of intoxicants.
2f
It is the Spanish expression for double-entendre.
7
The expression IDDQD comes from the video game called Doom. The expression is actually a cheat code for the game.