"the condition wherein the sufferers arse cheeks and or thighs slide past eachother with a worrying lack of friction during ambulation. The condition fequently occurs in association with itchy arse syndrome and high levels of shame."
"I was walking all round town shopping and I had the slips which really upped the shame factor. So I had to nip into Mcdonalds for a shame wipe"
The Slip is a maneuver performed by a guy where he tucks in a small portion of his shirt into his pants, while leaving the rest hanging freely. It can be done multiple times and is most common in the front and back.
Brad Pitt does the slip when he wants to look chill. Only the front is tucked in but everything else hangs out.