Formally known as the Tantus Feeldoe Slim.
It's a strapless strap-on designed to give skin-on-skin contact without breaking the continuity of action to adjust straps and buckles. It works! A person uses their internal muscles to hold it in place with the bulb as the shaft protrudes at a natural angle. The Tantus Strapless Slim is easier to hold and control than the original; the Slim is 10% lighter than the original model, making it lighter for the driver.