David R. Fleisher (Management of Functional Gastrointestinal Disorders in Children, 2014) wrote …

“Rumination can occur in patients of any age, from infancy to old age, and is ‘a broad spectrum of conditions ranging from short, benign and self-limited to severe and life-threatening.”

According to the same source …

“Benign rumination is the classic, best-known rumination syndrome. It is a learned, self-stimulatory, pleasurable habit practiced by neurologically normal adults and children who typically suffer no serious complications or comorbidities, although benign ruminators may be anxiety-prone or have obsessional traits. While most benign ruminators (including historically important individuals such as Samuel Johnson and Edward Brown-Sequard) practice their habit in private, a few exhibitionistic ruminators exhibit their regurgitative skills for the entertainment of audiences.”