The term used when there are five Friday's & Saturday's in one month to go out drinking. Months i.e in 2010 are January, July and October.
Jack (1st text on February 8th) - Where the hell did you get to at the weekend, we all had a wicked time :-)

Tom (1st text) - Sorry mate had no money, last month was an Expensive month. :-(

Jack (2nd text) - We all had way too much to drink, and I slept with your x :-O{

Tom (No 2nd text)
by monk tha hola the wonk February 20, 2010
Get the Expensive Month mug.