"Tgirl" stands for "Transgender Girl," referring to a transgender female or someone who identifies as a woman with male genitalia. In this context, "tgirl" is used to describe the performer receiving oral sex in the video. A "blowjob" is a sexual act where one person, usually the one giving oral pleasure, stimulates the genitals of another person with their mouth and/or hands. So, "Tgirl-Blowjob" indicates a porn video featuring a transgender female performer receiving oral sex from a partner.