Complex sentence: Emetophiles put emetophilia into practice by actually vomiting, especially on a partner, it is called a Roman shower, after the commonly-supposed (but mistaken) belief in the frequent induction of vomiting at Roman feasts.
Split into simpler sentences: Emetophiles put emetophilia into practice by actually vomiting, especially on a partner. This practice is sometimes called a Roman shower, after the commonly-supposed (but mistaken) belief in the frequent induction of vomiting at Roman feasts.