In British public schools, a fag is a young student who runs errands and does chores for an older boy. There are no connotations of homosexuality. You can find this term in a number of Victorian novels, but I have no idea if this term is still in use today.

I was reading E.W Hornung’s Raffles: The Amateur Cracksman this morning, and right there on page one Bunny Danvers blurts out to Raffles "But I fagged for you at school, and you said you remembered me." I was stunned, not because of what I thought the implications were, but because I never thought a Victorian era novel would be so explicit about the love that dare not speak its name. Turns out, after a small bit of research, I was wrong, and Bunny and Raffles will only be together in erotic fan fiction.