When a turd is ejected forcibly by gas into the toilet water, spattering water on the butt.
"I had a splashdown, and had to wipe my ass all over."
by townsick May 4, 2010
It happens in the middle of the night when you wake up with a massive dookie pain, rush to the bathroom and don't notice the toilet seat is up. A bare butt hitting cold water at 2am usually causes the person to yelp loud enough to wake everybody in the house.
Julie: "Eeeee-ahhhh!"
Kelly: "What happened in there?"
Julie: "You left the freakin' toilet seat up again! I had a splashdown!"
Kelly: "I bet you're awake now."
by SirJigglesAlot May 23, 2011
An event which may occur anywhere from a mans middle age to his elderly age. Upon sitting on the toilet the mans nut bag hits the toilet water.
Boy am I getting old. My ballsack hit the toilet water this morning...

That's called a splashdown Bob.
by Chaos_Elite January 18, 2017
A babies due date or more specific the exact moment when the waters break and shit gets real
No way , didn't know she was pregnant so whens splashdown ?
How long now until splashdown ?
by Lolly14 January 30, 2015
Often caused by excess alcohol consumtion. the act of urinating over people/objects while asleep, it is common for the person not to notice til the next morning
Great guys, Splashdown all over the sofa last night.
by boomboomchiccaboom June 21, 2010