The term is wrong as it likely involves sexual exploitation and inappropriate sexual descriptions which are not suitable for general discussion or dissemination. In a diverse and inclusive society, we should respect all people and not use such terms that can marginalize or misinterpret a group. Moreover, it violates the general standards of decency in communication.
Well, first of all, it may be associated with adult and vulgar content. Secondly, it can be seen as disrespectful to the bisexual community by reducing them to just sexual objects in a so - called 'story'. Also, it goes against the values of propriety and respect that should be maintained in all forms of communication.
It's wrong because it promotes sexual content in an open and perhaps irresponsible way. It may objectify people of bisexual orientation.