Double penetration dildo
A Double penetration dildo or double dildo is a sex toy that allows for the simultaneous penetration of two bodily orifices at the same time. It is designed in the form of two penetrative stimulators (penis shaped or non-phallic) that come separately or fixed on the single shaft. Some of them include a vibrating motor that turns them into double penetration vibrators. It is known in Japan as a "harigata".
The following three sexual configurations can be performed with using double penetration dildos.
Vagina-to-vagina. Some women use double-ended dildos as part of their sex play with a second woman. The double-ended nature of the dildo allows penetration in two vaginas simultaneously.
Vagina-to-anus.The majority of double-penetration dildos are designed for simultaneous stimulation of anal and vaginal erogenous zones, but it in the case of elongated "double-headed" devices it is possible for two partners to use the same device simultaneously. This can even be used for pegging, when a woman penetrates the anus of a man.
Anus-to-anus.All double-ended dildos can be used for anal penetration of both partners.
Simulated oral sex can also be performed on the dildo.
Double-ended dildo. Associated with lesbian love making devices, double-ended dildos are also used by heterosexual women for anal and vaginal simultaneous penetration. This dildo is usually made out of the soft flexible material (such as plastic or some form of rubber) that allows changing the shape of the shaft like the user wishes: to bend in the C-shape or to straighten it. In the past, though, they were often made of wood: Haberlandt (1899), for example, illustrates a straight double-ended dildo of this kind from late 19th century Zanzibar.
Anal and vaginal stimulators on the single shaft.These types of dildos or vibrators are intended for stimulating the user anally and vaginally. One shaft of the smaller length and width is attached to the other one that are both inserted stimulating anal and vaginal erogenous zones in a woman. In a vibrating sex toy there can be two motors in both shafts controlled together or separately.
Kits of two separate vibrators or dildo used simultaneously. This type is a kit of vibrators and dildos that are not connected with each other or connected by a wire attached to the single control panel. They are used simultaneously or separately stimulating the erogenous zones of both partners. This type is more mobile and one can offer much more possibilities for love plays with or without partner(s).
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.
Jelly rubber ("jelly").The most popular sex toy material that is convenient for designing any shape and texture of the shaft. It features a variety of colors, though jelly tends to suffer discoloration, and physical deterioration over time. This material contains chemicals called phthalates, which are thought to be harmful to gynecological and reproductive health. Unlike silicone (below) this material is porous, meaning that it can harbor bacteria.
Silicone. Dildos and vibrators made of this material are durable and feature excellent non-porous properties, so they are easy to clean and maintain.
Rubber. Many realistic dildos are made of rubber—a material that is both pliable and flexible enough for effective penetration. Like jelly, rubber is also porous.
Glass. Glass double-ended dildos are usually created with special original designs. Glass is a smooth and firm material that delivers a cool feeling when used. It can also be used chilled and warmed for different feeling. Usually, glass dildos are made out of a special borosilicate type of glass, of which Pyrex, Schott-Duranglas and Simax are the most suited.
Plastic.This non-porous and phthalate-free material is often used for creating double-ended dildos.
Concrete. These double ended dildos composed of cement and other materials such as fly ash and slag cement are commonly associated with the industrial fetish scene. There have been a number of serious anal injuries i.e fissures and tears in the skin of the anal canal due to the use of these dildos. As these sex toys are commonly home made and only available on the black market there is currently no safety testing or regulation to prevent such accidents.