intromission

Among the tuatara’s unusual reptilian traits are the relatively simple structure of its heart and lungs, the somewhat froggy style of its gait and the absence of any sort of male intromission organ, or penis.

From New York Times ● Nov. 22, 2010

To effect the former purpose, he made his only practical intromission in local politics, and made it unsuccessfully.

From The Works of Robert Louis Stevenson - Swanston Edition Vol. 25 (of 25) by Andrew Lang

"What, this lawless intromission to our face, and in our council too?" cried the baron.

From Traditions of Lancashire, Volume 1 by John Roby

Her first intromission in politics--but I must not tell you that story, the authorities have decided you are to hear it otherwise and from a livelier narrator.

From David Balfour, Second Part Being Memoirs Of His Adventures At Home And Abroad, The Second Part: In Which Are Set Forth His Misfortunes Anent The Appin Murder; His Troubles With Lord Advocate Grant; Captivity On The Bass Rock; Journey Into Holland And France; And Singular Relations With James More Drummond Or Macgregor, A Son Of The Notorious Rob Roy, And His Daughter Catriona by Robert Louis Stevenson

Deus nobis haec otia fecit!—Deus, by the intromission of one rarely good mother, and two rarely good, and I may add rarely gifted, wives!

From What I Remember, Volume 2 by Thomas Adolphus Trollope