Fisting is a form of sexual activity where one person inserts their entire fist or fingers into the other person's vagina or anus. In this context, "fisting gay" refers to a gay fisting scene, which involves two men engaging in fisting with each other. The term "gay" in this tag specifies the sexual orientation of the participants. This is a type of BDSM activity and may involve power dynamics or roleplaying within the scene.