Rarity wears an Aperture Science Portal Belt XXX — like a chastity belt, but with glory-hole portals over both orifices. Twilight has the controls, and the keys. There's a portal mask for oral, and Twilight has plans…

Contains some futa characters, including Twilight.

Consensual but not entirely safe or sane bondage.

Thanks to Bronyb3n for commissioning me to write this.