trap-on dildo (also strap-on, strapon or dildo harness) is a dildo designed to be worn, usually with aharness, during sexual activity. Harnesses and dildos are made in a wide variety of styles, with variations in how the harness fits the wearer, how the dildo attaches to the harness, as well as various features intended to facilitate stimulation of the wearer or a sexual partner.

A strap-on dildo can be used for a wide variety of sexual activities, including vaginal sex, anal sex, oral sex, or solo or mutual masturbation. Sexual lubricant can be used to ease insertion, and strap-on dildos can be used by people of any sexuality or gender.