There are plenty of couples' strap-on sex toys on the market and we have featured many of them. Vibrating strap-ons are the most popular to use with two-way harnesses since the design allows for both partners to experience penetration and vibration simultaneously in the G/P-spot. Another great way to experience double pleasure is to use a strapless strap-on with a plus size strap-on harness. A strapless strap-on can only be worn by someone with a vagina, as this is where the strap-on sits when in use.