When a male or futanariejaculates while being anally (or vaginally, in the case of futanari) penetrated by either an object or a body part.
It should NOT be confused for when a female ejaculates, in which case female ejaculation should be used instead. It also should NOT be confused with penis ejaculation inside a vagina that is being penetrated (cum in pussy). The person ejaculating is the one being penetrated, not otherwise. THE PERSON PENETRATED AND EJACULATING MUST HAVE A PENIS.
