A stream of urine that come out in one or more completely unpredictable directions, rendering even perfect aim futile. This creates a mess for the next person who cleans the bathroom. This typically occurs after sleeping in on Saturday.
Tina's gonna be so pissed, I Saturday Morning Pee'd all over the bathroom floor.
Sorry I'm late dude, I totally Saturday Morning Pee'd all over the shower curtain. I had to throw it in the washer before Lisa got home.