The Forest Flu is a sickness experienced by most people after attending the Electric Forest Festival in Rothbury, Michigan. The combination of wearing your immune system down after 4 straight days of partying, with sharing germs with people from all areas of the country, as well high levels of dust on the festival grounds, leads to a high percentage of festival attendees to report various symptoms that coincide with the common cold, influenza and sinus infections.

Forest Flu does not directly imply, but can include other diseases transferred through unsafe sex and unsafe drug sharing.

A casual invitation / threat used by an individual that is not afraid of fucking someone up.