Short for penis creases - the pair of visible ridges of flesh that skinny surfer types sometimes have on their lower abdomen, tapering down towards their groin.
A nice pair of peecees tend to get girls thinking about penises and going a bit weak at the knees.
Girl 1: "Did you see that dude with his board shorts low and no shirt on?"
Girl 2: "Oh yeah, he had sexy peecees!"
Both girls: *sigh*
Pajama casual is a term used when working from home and preparing for a video conference. All business above the waist and your pajama pants down below.