A guy or girl who pretends to be bisexual.
Often because they think it is cool and also to gain
attention from others (strangly normaly those of the
opposite sex.)
Bi-trendy people will often kiss but will go no further sexualy unlike people who are really bisexual, this is mostly done around others as proof of how bisexual they are.
Bi-trendy people also have an obsession with talking about how bisexual they are and want everyone to know it.
Emos seem to
be the best example of people who can be (but are not always) bi-trendy however anyone can be bi-trendy and i have seen it happen in many scenes.