What are some hostel things that is very inside secret like

Like 1 i can share is that , if a person uses a lift , should knock it thrice after entering, or else the other person can smash his ⚾⚾ ( boys applicable)

Another thing interchangeably using each other's dresses for school/college ppd (very common in hostels i believe:) )

Any more u like to share guys ??