While a double dildo obviously would provide stimulation to the wearer as well, the standard straight dildo is very poorly suited for harness use.

Double-ended attachments

To overcome this, many dildos are available for harness use that have an offset in the middle, with the main attachment and a smaller vaginal attachment for the wearer having a flat vertical section between them.

This way, the main attachment is at a good angle and position for thrusting, while its movement is transmitted directly to the vaginal plug and clitoris of the wearer.

Double-ended/sided hands and strap free dildos

The latest technological achievement is totally new kind of strapless strap on. A special example of these are Feeldoe, Sysil, Super Strapless Silicone Dildo, Share, Nexus Maximus and Transfer, which has an egg shaped bulb designed to be inserted into the vagina or anus of the wearer. Due to the shape of the dildo, thrusting on the main dildo translates to lateral movement of the plug, providing great stimulation to the wearer.

Additionally, the shape of the plug allows it to be used without a harness in many instances. It can also allow a man to perform a double penetration (actually doing anal while the dildo penetrate the vagina) while being anal-plugged himself, all with only a single toy.

Internal plugs

Many of the “professional” harnesses have one or two plugs (vaginal, anal, or both) on the inside of the harness, to penetrate the wearer. These plugs (may be shaped either like small dildos, the standard butt plug shape, or a combination/hybrid thereof) are usually firmly attached to the harness, and provide stimulation to the wearer as he/she thrusts with the main dildo.

Harnesses made for men usually only come with the anal plug, while ones for women come with both plugs, which most women report provides the most pleasure using one.

While a plug can be used in combination with most any harness, just by inserting the plugs before putting on the harness, all the harness tends to do is push the plugs in, and not move them as to provide stimulation when the wearer thrusts. Depending on the type of harness, different ways are used to properly attach plugs to the harness.

A common type consists of an opening or rubber ring with a cloth or leather back, similar to what might be used to hold the main dildo to the front of the harness, but positioned over the anus, vagina, or ones for both. A dildo/plug with a wide base is inserted through the ring, then when the harness is put on, the material pulls tight against it, holding it firm.

For vac-u-lock harnesses, one or two additional vac-u-lock plugs are mounted on the inside of the harness, allowing any vac-u-lock attachment to be used. Most vac-u-lock harnesses that have the connectors for internal plugs come with two plug-shaped vac-u-lock attachments, a smaller one for anal use and a larger one for vaginal use. Like other types of harnesses, both plugs may be used at once, and often are separately adjustable on the strap to fit the wearer’s body.