It is usually used to describe the air leakage phenomenon of a house or building structure, which means that the gap in the wall is too large or not completely sealed, which leads to the indoor air entering or leaking from the gap and makes the indoor and outdoor air circulate with each other. This situation may lead to problems such as difficult maintenance of indoor temperature, waste of energy or discomfort.
But some people use the meaning of two-part allegorical sayings to satirize some people, have it both ways, who gossip everywhere.