the inferior "earpiece" on your headphone set. for songs that use surround sound, where some sounds are only in one earphone but not the other. there is always one earphone that gets all the sounds, this is the superior earphone, the other earphone only gets some of the sounds. this is the bitch earphone.

it is vitally important when listening to an ipod/walkman etc with only 1 earphone in, that you dont put in the "bitch earphone"