The first part of a strap-on
setup is the harness, which connects the dildo to the wearer's body, usually in a position similar to that of a male's genitals. A good harness should be sturdy yet comfortable, and is often designed to provide stimulation for the wearer. Many different types of harnesses are available, with different features and drawbacks, and which harness is best is often a matter of taste, as there is no one "right" answer. Some dildos do not need a harness or are built onto one; for these, please see the sections on dildo types and dildo attachment methods.
A 2-strap harness with dildo
; the outer strap goes around the wearer's waist, while the inner strap goes between his/her legs
2-strap- A 2-strap harness, in its most basic form, is similar to a g-string. One strap goes around the wearer's waist, like a belt, while the other goes between his/her legs and connects to the other strap in the middle at the lower back. While these are simple, many people find them uncomfortable because to the strap rubs against the anus and other areas, and they sometimes do not hold the dildo very firmly, causing it to sag, flop, or twist.
A 3-strap harness with dildo; the outer strap goes around the waist, while each inner strap goes around the thigh and rejoins the waist strap forward of the hip
3-strap- 3-strap harnesses also have one strap around the wearer's waist, but instead of one strap between the legs, have two straps, one around each thigh, rejoining the first strap near the front. This design leaves the genitals and anus uncovered, and attaches the dildo much more firmly, giving the wearer more control. However, not all people find this design comfortable, and sometimes they are hard to make fit properly or tend to slip.
2 straps or 3? 3 straps or 4?- A variation on these designs, usually on harnesses which mount the dildo substantially lower (on or near the vaginal opening) rather than higher up, has a continual waistband that is not part of the dildo mount or backing, with a V-shaped pair of straps in the front, and either the single strap between the legs or the two straps around the thighs. The former of these is called a 3-strap, and the latter a 4-strap, however most of the aspects of their design and use (such as a strap over the anus, etc) are the same as 2-strap and 3-strap harnesses, respectively.
Corsets and other clothing items- Strap-on harnesses built into various clothing items are available, most often as a corset or other item of lingerie. Some are designed to be worn underneath normal clothing for quick use (if done with the dildo in place, either to give the appearance of a penis or to be able to quickly initiate intercourse, this is sometimes called packing), while others take advantage of the additional strength and sturdiness an item of clothing can provide over a few straps, or just to integrate the strap-on into an erotic outfit.
Thigh, Chin, and other locations- Harnesses are not limited to the crotch, and indeed many types are available for other body parts. A popular one is a thigh harness, which attaches a dildo to the wearer's thigh (or other part of the legs or arms, though this is much less common), allowing for many unique positions, as penetration is no longer limited to what could be done with a penis. Another unusual design attaches a dildo to the chin of the wearer, allowing vaginal penetration while performing cunnilingus
Furniture, beach balls, and other objects- Harnesses are available to attach dildos to just about any household object, allowing for many creative uses. A dildo could be attached to a chair, bed, or any other item of furniture, and penetrate someone during other activities, with or without a partner. Another item, while not technically a harness, but worth mentioning, is an inflatable ball, usually 9 to 18 inches (250 to 500 mm) diameter, made of sturdy rubber designed to support the weight of one or two people, with an attachment for a dildo on it. This allows many unique positions, such as double penetration for a woman by laying face down on the ball for vaginal penetration
while her partner penetrates her anally doggy style, which is much more effective than a solid object due to the "bounce" of the ball. These inflatable balls are also quite popular for solo use.