A person that usually drinks plain coffee flavored coffee, but sometimes likes to have a flavored Starbucks coffee.
Bill: Dude I thought you only drank black coffee.
Dude: You know Bro sometimes I gotta run by Starbucks and have half caff mocha with a shot of butter scotch.
Bill: Dude, You're bi-coffeexual.
Dude: yes but I like plain coffe most of the time.
Bill: Being bi-coffeexual, there is nothing wrong with that.