When a guy is masturbating and as the first shot of cum shoots in the air, the guy immediately does a 180 on his back and the cum lands gracefully on his back.
The area around the base of the urinal or toilet whereupon piss splashes whilst a person urinates. Not to be confused with 'splash zones' around swimming pools or at water parks.
"Honey would you please move your bunny slippers? They're in my splashzone."
Mike: Dude, after my shower I was bending over to grab my boxers and my butt hit some other dude who just got out of the shower Phil: Oh, so you had a Splash Down
(1)when you have the shits so bad that the turd-el-wave splash the water out of the t-bowl
(2)The jet of water that shoots up your ass when you launch a rocket off in an airport bathroom.