插科打诨 is a four-character idiom formed from two verb-object constructions: 插科, where 插 means "insert" and 科 refers to "stage actions" in theatrical context, and 打诨, where 打 means "engage in" and 诨 means "jokes". Literally combining "insert actions" and "make jokes", it directly describes the act of interjecting comic elements into performances, as seen in traditional Chinese opera.