A strap on is an artificial phallic appendage or dildo that can be strapped on to allow a person without a penis to have penetrative sex. Strap ons are also used by people with penises to provide a harder/better erection, or to provide the person's partner with a different penetrative experience than a real penis provides. These are referred to as male strap ons. A strap on is attached with a belt or harness and is designed to sit in a similar position as a biological penis. Newer strap-ons eschew the straps for a sturdy, comfortable pair of underwear with a dildo attachment in the front.
Strap-ons may be used for penetrative vaginal sex, anal sex or pegging. Some people also enjoy giving a strap-on blow job. Although the recipient can't feel the fellatio, the act does provide a powerful visual.
When buying a strap-in, look for high-quality materials, fit and comfort and the how the dildo is attached.
Strap ons may also be referred to as strap-on dildos.