It allows the user to create a perfect imagery of a weapon made from the same material the user just bad bitten to. For Sabro's case he wears a necklace so that it makes it easier for him to bite into the materials, which notably are gold, silver and copper. His father appears to have 5 different metal tags engraved on his necklace.
List of Weapons
- Mairimashita! Iruma-kun Anime Episode 5