Gender Euphoria is the opposite of gender dysphoria and is the comfort or joy experienced when one presents as, or is viewed as one's true gender and/or joy experienced when imagining oneself as a given gender. Gender euphoria is a sign that someone is transgender even if they don't experience gender dysphoria. For example, someone may not feel dysphoria when presenting as their assigned gender at birth, however they may feel gender euphoria when presenting as or identifying as another gender.
Like with gender dysphoria, gender euphoria can come in three different types. These are body, social, and mind.
Body euphoria is the joy experienced after medically transitioning or when imagining one's body after transitioning. This can include euphoria about one's chest (the lack or breasts in the case of trans men, having breasts in the case of trans women) or one's genitals. Body euphoria can also include euphoria about one's voice, body shape, facial features, body hair, etc.
Social euphoria is the joy experienced when one is gendered correctly, or when imagining oneself being gendered correctly. This can be experienced with friends, family, or with strangers. It includes euphoria experienced when being called by the correct pronouns, the correct name, or the correct gender terms (Mr. Miss. Mx. Boyfriend, Girlfriend, Enbyfriend etc.)
Mind euphoria refers to when one's thoughts or emotions reaffirm their gender identity. This typically is seen in being confident in one's gender, and not having feelings of self doubt. It can also take the form of emotional reactions to situations. Trans people who take hormones often find that their emotions react differently, for example trans women may find that they cry more easily and have more emotional reactions. Trans men may find that it's harder to cry. People taking hormones also say that some emotions, like anger feel different or are in a different place. For example trans men may feel anger more intensely or in a place (such as feeling anger in one's face pre-hrt and feeling anger in one's chest post-hrt).