The activity of negative loitering, usually partaken by fools. Most commonly used in third person.
A congregation of lower class individuals are milling around MacDonalds, hindering you reaching your desired destination.
"Stop milling around the place, 'cause you know you're just a fool"
A slag, who after a variable amount of time, is in fact deemed to be in a bag.
Being 'in' a bag could include - living, shitting, having intercourse within the confines of a bag
'Who is that milling around the place? Is it just a fool?'
'No, it is rather a slag in a bag'