``Habitual passive sodomite takes knee-chest position without shame during examination." —From Principles of Forensic Medicine by staff members of the Forensic & Clinical Toxicology Department. Ain Shams University Faculty of Medicine.
Forensic examinations to prove habitual non-violent anal penetration are inherited from the textbooks of Victorian era medicine.
There are no peer-reviewed research that provides sound evidence in that area. Because sodomy was decriminalized in western Europe by the beginning of the 20th century. While countries that still considers such acts criminal are not publishers of sound peer-reviewed research.
Today, most of the descriptions inherited from old text books are easily discounted.