Onmund's Request Edit
Crotch Guzzler, now Arch-Mage, speaks with Enthir to get him to return something that he had of Onmund's. Enthir will not give back what he got from Onmund unless Crotch goes to fetch a staff for him. (Tolfdir's Accident)
Crotch goes out to a cave full of vampires to get Enthir's staff and possibly try to recruit them to the College of Winterhold. After retrieving the staff, Crotch returns to the college to be harassed by Enthir then give Onmund his stupid amulet back. (Sex with Brelyna)
Talking about Gallus Edit
S'oggy Balls, looking for somebody to read Gallus's journal for him, goes to Enthir, who used to know Gallus back when he was a scholar at the College of Winterhold. Unfortunately for S'oggy, Enthir cannot read Gallus's journal and directs him to Calcelmo in Markarth. He also talks nostalgically about Gallus, who he reveals that he climbed through windows to get hand jobs all the time. In fact, that's how Enthir met Gallus. Gallus climbed the window into Enthir's laboratory.