Bigenderlean is a gender in the bigender system which one has two distinct genders that that they are fluid between. One can be one gender or a mix of the two genders, but never the other or fully both. This gender can change abruptly or can work like a sliding scale, sliding between different ratios.
An example of a bigenderlean individual would be someone who is fluid between man and non-binary. The individual could be man or a mix of the two, but never be non-binary or fully both non-binary and man.
The flag was created by the coiner in the coining post, on the same date. The blue represents the one of the genders that one is fluid between. The larger stripe that it is represents it is the only gender you can feel separately from the other. The colors in between represent a mix of the two.