they would probably be considered offensive to horse girls or it's really only ok for them to say it to one another.
I'd say it'd mostly depends on the implications of the saying. Again "quit horsing around," or "hold your horses," could just be a way of saying you have high energy. Hell, Oguri and Special Week almost make me certain "hungry as a horse girl," definitely exists lol. That being said, "don't look a horse girl in the mouth," could be a rude way of calling a trainee a poor second pick, or just straight up old.
