A vanilla audience is a form of public humiliation practiced by BDSM couples. During this humiliation, the submissive is compelled to perform demeaning acts for the dominant partner while invited guests watch. Having the guests witness these acts and vocalize their feelings adds to the submissive partner’s humiliation.
While a vanilla audience may seem cruel to outsiders, it's important to note that, as with all BDSM activities, this type of humiliation is consensual.