The plug of a dildo mouthpiece is a prosthetic penis. There are some dildo gags that are externally fitted with a dildo that allows the user to have intercourse for others.

Unlike other sadomasochistic activities, wearing a gag has little potential to cause physical harm, but there are risks.

Wearing a gag for a long time or wearing a gag that is too large may cause jaw damage

The strap of the gag may abrade the skin of the wearer

Wearing a solid mouthpiece when nasal breathing is poor may cause asphyxiation

The stuffing may cause vomiting

When buying a mouth plug, care should be taken to select the size of the mouth plug, and it should be removed in a timely manner after a period of use. Wearing a mouthpiece should be careful to keep the wearer breathing well to avoid asphyxiation. Since the wearer is unable to speak, both parties to the sadomasochistic activity should discuss a movement as a safe word.