If the same girl wakes up in your bed for the majority of a week (x greater than or equal to 4) then you are contractually obligated to engage into a relationship with this individual. This rule does not apply when on vacation, due to the fact that there are frequently less beds and arrangements need to be made to satisfy both parties.
Dude, my roommate just satisfied the four day rule, that must mean they're dating. Sucks for him...
by Tyrone Schiff February 19, 2006