When one's housemates/family have irritated or wronged oneself in some way, he or she may choose to invoke "public milk" out of spite. This practice involves chugging milk straight out of the carton without telling anyone, and works especially well if one has any prexisting contagious medical conditions.
"my flatmates came home really drunk last night and woke me up, so I public milked them"
"the other day my step-sister invoked public milk, and now I have the flu"
September 22, 2012