This porn video tag "pre-t-ftm" stands for "Pre-Testosterone Female-to-Male."
In the context of adult content, it refers to a category of videos featuring transgender or gender non-conforming individuals who are in the process of undergoing hormone replacement therapy (HRT) with testosterone as part of their transition from female to male. These videos may showcase various aspects of sexuality and gender exploration involving these individuals during this phase. It's important to note that this tag is primarily for adult audiences who are familiar with the terminology and context related to transgender experiences in pornographic content.