Traditionally a booty call is when you contact someone late night for a sexual rendezvous. It used to be a phone call, but nowadays booty calls are made via twitter, facebook, texting, or the reliable old 2am phone call. No matter how you make your booty call, it's obvious you are looking to have sex, no strings attached. Often times it is an ex that you are booty calling, but it doesn't have to be. Booty calls can be made between any two partners, male or female. You will never know unless you pick up the phone and make that booty call.
Need a new booty call?
Most of the time, a booty call is someone you have known for a while or are familiar with. Familiar enough to call them in the wee hours of the morning and ask to be inside them, or vice versa. But what if, when feeling the need for your booty call, you feel the need for some strange? Like a booty call with a complete stranger. Obviously, you want to check them out first. They have tons of websites devoted to booty calls (or "casual dating"), where everything is out in the open. You go on, browse for a booty call, send him / her a message, and get it crackin.
There have been other uses of the phrase 'booty call,' including a movie and a popular web video series.
Booty Call the movie
Pretty funny movie that came out in 1997 starring Jamie Foxx, Tommy Davidson, and Vivica Fox. Kind of goes against the nature
of a booty call with all the cupcaking and DTM (DoingTooMuch) by the guys, but still vaguely entertaining.
Booty Call the web series
This was a web video series / flash game on the site Romp.com. Basically it followed this guy Jake around and you could control his sexual conquests by tweaking his "game" as he hit on various women. Definitely funnier than the Booty Call movie. I acutally watched this a lot in the early 2000's, when Romp.com dominated (and burned millions in VC). I still remember Jake's signature phrase, "I'll have a jack and coke..... AND A BOTTLE OF DOM!"
Apparently they made a movie of this drivel, and it has the dubious distinction of being the first film ever created entirely in Macromedia Flash. I saw it, it's junk. But if you can get your hands on the original flash games / webisodes they are gold.