A he/him lesbian refers to a lesbian who uses he/him pronouns but is still a woman or woman-aligned. Those pronouns can be exclusive or one can be multipronoun. It is a more specific form of pronoun non-conformity and crosspronoun usage. A he/him lesbian does not identify as male. They may acknowledge that they are female, but pronouns are usually inherent to specific identities. That being said, 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.
A 'disconnect from womanhood' is a common experience among he/him lesbians. Similarly to how lesbians might go by masculine names or present as a butch, a lesbian may refer to themself by he/him to express this disconnect from their gender. This term is only used to identify people who do not consider pronouns to be explicitly linked to gender identity.
A he/him lesbian can be a cis woman or a trans woman. However, he/him lesbians don't always include trans women use who he/him pronouns purely because they are not out yet. He/him lesbians only include those who actively identify with and want to go by he/him pronouns for the most part.
The existence of he/him lesbians has been the subject of controversy, more so than other pronoun-sexuality contrasting identities (excluding they/them lesbians). This is typically based on the misunderstanding he/him lesbian's gender identity and on the false assertion that a person's pronouns must be directly associated with their gender.
Trans Men vs. He/Him Lesbians
The term "he/him" lesbian has been criticized by some trans men and allies as being disrespectful to them and Invalidating their experiences. Some have argued that people who identify as women and use he/him pronouns invalidate the dysphoria that trans people feel.
She/Her Lesbians vs. He/Him Lesbians
Some she/her lesbians and allies have argued that the term invalidates she/her lesbians (due to the he/him lesbian experience of "disconnection from womanhood"), and romanticizes the past experiences of women forced to use he/him pronouns to avoid persecution.
The he/him lesbian flag was designed by Tumblr user Wuvsbian.