That is a cool looking gag. The most extreme I've seen, outside of hoods with breath play, such as gas masks and vacuum sealed type latex, was gag that strapped around the face with a tube for the mouth that was fed from the slave's urethra. A client brought it in for an intense, 4 hour session that was largely focused on bondage. I was a little uncomfortable with it at first, not wanting him to choke as he would be in all types of positions. But, he had extensive experience with it, walked me through everything and we had hand signals if he got into trouble and was unable to speak. I've never seen one before or since.
