Definition of "irrumation"

In this setting the thought of self-irrumation occurred to him in May, 1923.

1939, American Psychiatric Association, The American journal of psychiatry, Volume 95, Part 1

He had, back in Cambridge, taken one of Jem Follett’s boys for a penny, an envisioned Tom Walsingham in his head like a god and the motion towards irrumation like a prayer.

1993, Anthony Burgess, A Dead Man in Deptford

Anal intercourse is reported in between 6-26% of female complainants, but it is important to remember that there may have been a number of different sexual acts performed by the assailant, including irrumation (forced oral penetration) or cunnilingus.

2006, Baguley, Kumar, and Persad, Key Topics in Sexual Health, Taylor Francis, p. 56