It's like a regular party, except there are a few exceptions. It's a party that a small group of guys have that involves drinking solely white russians, and the chicks invited are hookers for each guy. Generally White Russian Parties are held in hotel suites.
Guy 1: Dude, lets have a party!
Guy 2: Sweet, we'll have a white russian party!
Guy 1: What's that?
Guy 2: It's like a regular party but better because you're house doesn't get trashed, you get guaranteed sex with hot bitches, and you get to drink white russians!
Guy 1: Fuck yeah dude! What are we waiting for?