How do you explain this sentence when you are twenty-eight years old and have many forms of demons? They kill ordinary people with a sword at their waist.

These are two warning verses. The literal meaning is: beautiful women in their twenties and eighties, with enchanting postures, their bodies as smooth as butter, and a sword tied around their waist, which can kill ordinary people in the world. The extended meaning is: beautiful women are addicted to wine and lust, and if you get caught up in it, you will lose yourself and be at the mercy of her. Their body is an invincible murderous sword.

The above is just my personal understanding, I hope it can help you.