Homo-sensei
An open homosexual (or gay person) who takes on the responsibility of answering a new gay or questioning person's questions about GLBT related topics. Derived from the japanese word 'sensei' meaning 'teacher'.
GUY 1: "Dude, I didn't know they were friends."
GUY 2: "They weren't, until the older one became the younger one's homo-sensei."