A she/her gay is a specifically tailored identity that refers to a gay man who uses she/her pronouns. The term can be used by any men who are mlm (achillean) and use she/her pronouns. Those pronouns can be exclusive or one can be multipronoun or pronoun non-conforming.
There also exists he/him lesbians, they/them lesbians, and they/them gays.
She/Her Gays vs Trans Women
A she/her gay does not identify as female. She may acknowledge she is male, but pronouns do not always equal gender identity, as a she/her gay is simply a more specific form of pronoun non-conforming gay men.
It is a common misunderstanding that she/her gays "make the transgender community look bad", but that is simply the fault of the people who refuse to think about the subject or break down the concept to understand it. Oftentimes, pronouns are gendered but in some cases they're not despite what society says. The pronouns one uses are another part of gender expression, just like one's clothes or behavior. In the same way some non-binary people are more comfortable using pronouns other than they/them, some binary people feel more comfortable using pronouns other than the one's typically associated with their gender.
Flag
The she/her flag was designed by Tumblr user Wuvsbian on May 22, 2018 following their he/him lesbian flag.