Is sodomy without penetration considered sodomy, or is it one of its preliminaries? And is it to be analogized to fornication in this regard, along with a request for a definition of sodomy and when it occurs?

What your colleague did is forbidden (haram) and is among the sins that necessitate repentance. Allah Almighty has forbidden approaching zina (fornication/adultery), and sodomy (liwat) is even more strictly prohibited. Allah commanded the preservation of one's private parts except with one's wife or what one's right hand possesses (a bondswoman). And whoever repents and turns to Allah should conceal his sin, perform many good deeds and acts of obedience, and not speak about these matters unless for a legitimate Sharia purpose. Sodomy is a man having intercourse with another man in his anus.