In this sentence, "promiscuity" can be understood as the meaning of being prone to feelings or overflowing feelings, while "deep affection" means that the songs are sincere and profound in emotion and can move people's hearts. This sentence can be used to describe some specific places or situations, such as bars, cafes, cinemas and other places that are easy to make people feel emotional, or in some specific festivals, anniversaries and other occasions where music is needed to adjust the emotional atmosphere.