Beta 1.0
Even more than the different types of harnesses and dildos, there are different ways to make use of a strap-on setup. Generally ways of using them can be divided into several broad categories, however there are infinite variations.
Pegging is when a woman uses a strap-on dildo to penetrate her partner anally, usually a man. While this practice is not commonly mentioned due to the various taboos many cultures have against receptive male anal sex, and statistics are hard to come by, many people believe it is the most common use of strap on sex toys and dildos, and often manufacturers use images of a woman with a strapon and a male on the advertising or packaging for strap on dildos and harnesses.
Pegging can be done for a variety of reasons, but probably the most common is that it allows a heterosexual male to receive anal pleasure. Pegging is typically reported as extremely pleasurable for both partners, and many men have an anal orgasm from it. Many people, such as Dan Savage, believe all men should try pegging at least once, as it may introduce them to a new enjoyable sexual activity.
When pegging, even more than for other forms of anal sex, proper selection and quantity of lube is extremely important. Many dildos do not "hold" lube as well as a penis would, and a thicker or better adhering lube will likely perform much better.
A number of how-to videos about pegging have been made, for couples interested in trying it but not sure where to start, however most people feel a few minutes of experimenting to be plenty to learn the basic "ins and outs" of pegging.
Lesbian intercourse is what comes to mind when most people think of strapons, and certainly is one of their more common uses. Penetrative sex (either vaginal or anal) can be extremely pleasurable, and strap on dildos allows women to enjoy this sensation with their sex partner.
Men with erectile dysfunction may use a strap-on to help satisfy their partners, either by using one with a hollow dildo, or by having their penis hang beneath the dildo.
Some women find simultaneous vaginal and anal penetration to be enjoyable, and aside from using a double-penetration dildos discussed previously, can experience this with a male partner using a strap-on. A harness is selected that allows the man's penis to extend under the dildo of the harness, thereby allowing him to insert both his penis and the dildo into his partner. In a face-to-face position (such as the missionary position) the penis would penetrate the anus and the dildo the vagina; in a position such as doggy style the penis would penetrate the vagina and the dildo the anus.
Non-traditional harnesses, such as furniture attachments and ride-on balls, can be used for masturbation by both men and women. A ride-on ball can take the position of another person, in that it can be on bottom for most positions that have the person being penetrated on top, and furniture harnesses can be attached to many objects, an example being a bathtub, to penetrate the user doggy-style before or in a bath.
Some transsexuals may use a strap-on to provide the function of a penis, for example a female->male as he was not originally born with one. This is an option for people who do not wish to undergo surgery, for any one of many reasons. Strap-ons may also be used my male->female transsexuals, as one may not want to use her penis.
Many people, using a strap-on for any of the above purposes, often like to either suck or have a partner suck a strap-on, performing fellatio on it. The reasons given vary, but mostly have to do with power or role reversal, however, this activity is less common than simple penetrative sex.
The uses for a strap-on are limited only by the imagination of the user, and virtually all positions "normal" sex can be had in can also be done with a strapon, plus with thigh, furniture, ride-on ball, and other harnesses, many more that can't be done normally. Two people can simultaneously penetrate each other, for example, and virtually any other idea that that can be thought of (and obeys the laws of physics) can be done with a strap-on or two.