Love this series, but the attitudes towards being bisexual in this episode are grossly out of date and offensive, as was the whole scene where two men argue that women aren't as good at pleasing each other compared to men pleasing women because they don't have it- and then this is seemingly reaffirmed by events later in the episode.
For the record, Curb, like It's Always Sunny, usually dances around a lot of political subjects without necessarily advocating for one point of view - characters do and say offensive things all the time in these series, but it's always with a tongue in cheek attitude, winking at the audience. This wasn't that.
Review of The Bi-Sexual
