an abstract noun that is used to denotes the non-sexual, highly emotional relationship (nearly romantic) between a homosexual male (fag) and a heterosexual female (hag)
Possibly originates from gay Author Dan Savage, who also does weekly Podcast called "The Savage Lovecast", in his podcast he has addressed various issues of relationships, sex, sexuality, fetishes, and other sex related topics, and issues of Faghaggery in his Podcasts
There are many ways to use the word Faghaggery e.i. "If that guy is bi, she's not his hag, that's not faghaggery."
e.i. "what in the name of faghaggery is going on here"