Used to describe someone who claims to be bisexual, but really isn't. Usually, these people tell others that they are bi, either because
A) they think that it's cool to be bi.
B) they can't deal with their inability to understand the opposite sex.
A: Hey, I heard that Jennifer said she was bi!
B: Naw dude, she's a 7th grade bisexual dude. She wouldn't do it with another girl.