Extrashirt that comes partially untucked because of movement such as raising ones arms and makes one look like one is flabby. Especally when the shirt is a dress shirt with a tshirt underneath.
After a long day at McQuaid Phil had a large amount of shirt flab hanging out.
A response given to a movie theatre ticket collector when they ask you what that bulge in your sweater/jacket. What it really is is candy/food that the user purchased prior to entering the theatre to avoid stupidly high consession prices.
Cinema employee: "Ticketplease, theatre 1, first on your left. Ohh, excuse me sirr! What is that bulge hanging behind you."