Regression, as with most psychological concepts, covers a range of behaviors.
This returning to an earlier developmental stage can be as minor as returning home for the holidays, realizing your parents are getting older and instead of facing that fact, returning to ways of being and interacting that were more common when the person was growing up with their parents.
For individuals who are in the process of figuring out their gender or sexual identity, this might look like reverting to presenting and acting as you did before you started changing or realizing who you truly are. Sometimes this is an unhealthy regression and an avoidance of dealing with the family’s discomfort. Sometimes this is a planned, healthy means of remaining safe enough in an unhealthy family environment.
On the other side this can look like a person who grew up in an abusive home and having to rerun there for the holidays. This could lead to a dissociative episode in which the person becomes the child or teenager they were when they lived with their parents.
Either way, it is important to be aware of this pull to regress particularly around the holidays and the tendency to return to the homes we grew up in and getting triggered there.
Be prepared, know what types of things might trigger this regression. Look back at what has come up in the past, what’s been triggering and what other, healthy coping strategies you may have. Talk to your therapist, talk to your partner, get support.