Anal rail gun

The act of suppositing a large, mortar shaped metal butt plug into the anus, then nipping down to your local hospital for your MRI scan.
The magnetic resonance has been known to instantly accelerate the supposited metal object up to the speed of sound and deposit it elsewhere in the torso.

"Hey Arthur, did your wifes hospital appointment get in the way of your sexy weekend away?"
"On the contrary Jim, we were banging like the shit house door when the plagues in town. Hospital appointment looming and with her voyeuristic ambition, things got really sexy and I coaxed her into an anal rail gun.

anal rail gun

To wear,insert,or make use of a metallic Buttplug, while in an MRE machine.

Step 1. Wear a buttplug with a metallic core, or just wear a fully metal buttplug in your rectum

Step 2. Schedule an MRI or have a Walk-in MRI at your local hospital. While still wearing the Buttplug

Step 3. Lay on the MRI table and let nature takes it course.

As soon as the MRI machine is turned on, the buttplug will shoot at the speed of sound itself into your anal cavity, through it, and into your chest cavity.

Chance of survival is Low, but not impossible.

"Man, That Anal Rail Gun was intense! I gotta remember to take out my plug next time!"