A mouthpiece that can be inflated or deflated to change the size of the plug, usually made of rubber, with an inflatable device. Inflatable gags are not very practical because the size of the user's mouth varies and can easily cause vomiting.

Some inflatable plugs do not have an elastic band and may need to be used with other plugs.

Unlike other sadomasochistic activities, wearing a gag is unlikely 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.