a serbian air raid is when a man enters a public restroom to defecate. he then enters the stall, pulls down his pants and begins. the air raid part is when the two men in either stall on either side of him then proceed to both defecate and masturbate on the first man's head, as he defecates and masturbates. its a mess.
"Dude, I need a shower, I just got done with my first serbian air raid."
"Oh man, you should've called me, I always wanted to take a dump and jerk off on your head simultaneously."