... Pardon me, good person, but sissies aren't gay, they are their own gender, a very feminine person with small male genitalia with a preference for masculine people....
Not really either by real life use nor F95 tags. Also with a side dish of don't try gatekeep.
A sissy does aim for femininity in attire and presentation, but its not a statement of passability in that regard as "trap" or "twink" often imply, somebody who has very masculine features can still be a sissy, including genitalia.
Also while generally not dominant, the term doesn't imply a preference for masculine people either, and sissy characters feature widely in femdom and futa stories, not only gay ones.
That tag is used here correctly. ( Sissification [Dressing a submissive partner as a woman and/or encouraging/training to act in a feminine manner.] )