Nocismasexual

Nocismasexual also called Nesoic is the attraction to all genders, except, either: A) One's attraction to men fades once it is known someone is a cisgender man. B) One does not feel attraction to men until it is known that the man in question is not cisgender, or C) One chooses not to date cisgender men/chooses not to date men unless they know the man in question is not cis.

The term is used by transgender, non-binary, or otherwise non-cis individuals who are not attracted to cis men or are unwilling to date cis men. The unwillingness to date cis men is not because there’s any inherent difference between cis and trans men, rather it stems from issues of safety, trauma, oppression, or other personal reasons. One may not want to be vulnerable to misconceptions, misgendering, or oppression from their partner. One may also prefer a trans partner because one would relate to them more.

History
It's unknown when the term was coin or by whom, but it existed at least before November 2016.

The alternate name, nesoic, was coined on February 8, 2018 by Tumblr user identity-workshop. It was named after a moon of Neptune, as it is considered a subtype of neptunic.

Flag
The first nocismasexual flag was create on or before November 5, 2016 by Mod Raleigh from pride-flags-for-us. No meaning was given for the flag.

The second, and most commonly seen nocismasexual flag was created by Mod Hermy from pride-color-schemes on June 7, 2017. The blue being at the bottom represents discomfort/unwillingness to have a relationship with a cis man. The rest of the colors being represents how the person can be comfortable and fine with other genders/people.

An alternate flag was created by Asphyn Falwell (Oddlyasphyn) on June 28, 2020 on the LGBTA+ wiki. The light blue triangle represents cis men. The dark blueish-grey outline around the triangle represents the separation and disconnection between cis men to any other identity. Finally, the greys represent the gender spectrum.

Another alternate flag, based on the design of the original, was created on July 30, 2020 by Tumblr user Rainbowcoric. The black outer stripes, as well as the line striking through, represent the lack of attraction to cis men or the decision to not date cis men. The dark blue represents cis men. The medium blue represent any kind of t4t (trans-for-trans) attraction. The white stripe represents the trans people using the label.

Another alternate flag was created by Akoimiz on Tumblr on September 25th, 2020. The colors represent attraction towards different genders. Green represents agender people. Pink represents trans women. Blue represents trans men. Ivory represents non-binary people. Yellow represents multigender people. Orange represents genderfluid and genderflux people. Red represents cis women.