Billing and cooing is a term that refers to the sounds made by lovebirds when communicating with each other. It is a phrase that is commonly used to describe couples engaging in affectionate behavior. However, there are several other synonyms that can be used to describe this behavior. Some of these synonyms include whispering sweet nothings, exchanging glances, cuddling, smooching, and hugging. All of these words describe the intimate actions shared by couples in love, and they bring to mind the idea of affection, attraction, and romance. These words can be used interchangeably with billing and cooing to describe the actions of lovebirds and couples in general.