Suction cup dildos: how they stick – and on which surfaces

A suction cup—or suction cup—stays in place through air pressure. When you press it against a surface, the air is pushed out underneath the cup, and the pressure from the air outside keeps it in place. Anything that lets air in under the edge makes it come loose. That’s why it’s almost always the surface—not the suction cup—that determines whether a suction-cup dildo stays put.

Three things need to be right. The surface must be smooth and sealed. Both the surface and the cup must be clean and lightly damp. And the dildo’s weight must be in a reasonable proportion to the suction cup size. If all three are right, a suction-cup dildo will sit firmly on a tiled wall, a mirror, or a bathtub rim. If one of them isn’t, it comes loose—often at the wrong moment.

Below, we go through which surfaces work, why a suction cup releases, how you attach it, and which models also work in a strap-on harness. If it’s your first dildo, the basics are in your first dildo.

The principle is simple: the surface must be so sealed that no air can get in under the cup, and so even that the cup’s edge makes contact all the way around. Manufacturers describe it differently—Pipedream states for King Cock that the suction cup sticks to most smooth surfaces—but the physics are the same for everyone.

Tile and klinker with a glossy surface, glass, mirrors, glass tables, enameled surfaces like a bathtub side, painted sheet metal, painted wood, and other glossy, hard plastic. What they have in common is that the surface is completely sealed and smooth. Tile works best in the middle of the tile—grout under the cup lets air in.

Floors can work if they’re smooth, sealed, and clean, but many floors have a texture or a matte surface that prevents the suction cup from getting a tight seal. A glazed klinker floor is a better choice than a laminate floor with a wood imitation.

Untreated or oiled wood, porous stone, concrete, painted plaster, wallpaper, textiles, carpeted surfaces, and most laminate floors with a texture. They have tiny pores or unevenness that lets air in under the edge, and the cup loses its grip after a while even if it initially seems to be sticking.

Also avoid surfaces that can be damaged. A strong suction cup that is pulled off at an angle can, in the worst case, take color from a painted surface or leave marks on sensitive materials.

1. Clean the surface. Wipe off dust, soap residue, and grease. Soap residue is the suction cup’s worst enemy in the shower, so rinse the wall first.

2. Clean the suction cup. Rinse it with lukewarm water and make sure there’s no hair, lint, or lubricant on the underside.

3. Lightly moisten. A thin film of water on the cup or the surface helps the edge seal. It should be damp, not wet—and not lubricant, which makes the surface slippery.

4. Press straight. Place the cup flat against the surface and press in the middle so that the air is pressed out evenly in all directions. A cup that’s pressed at an angle creates a leak at the edge.

5. Let the lubricant end up on the shaft, not on the base. If lubricant runs down onto the suction cup during use, it can cause it to release. Wipe the base off if that happens.

To get it off: lift the edge gently with a fingertip so that air gets in, rather than pulling on the shaft. This saves both the surface and the suction cup.

A suction cup’s holding power grows with the area—meaning with the square of the diameter. A cup that is one third wider has almost twice the surface area to hold with. At the same time, a heavier dildo pulls harder on the attachment, especially on a wall where the weight hangs out from the surface.

That’s why it pays to compare weight and suction cup.King Cock 15 cm has a suction cup of 6,6 centimeters under a product that weighs 211 grams. King Cock 23 cm weighs 577 grams but has a suction cup of 9,2 centimeters. Silexd Silex-D 17,6 cmWeighs 251 grams on a suction cup that is 6.7 centimeters.

The counterexample is Silexd Silex-D The Original, which weighs 460 grams but has the same suction cup at 6.7 centimeters as the series’ significantly lighter models. This doesn’t mean it won’t stick, but it becomes more sensitive to the surface and likely sits best on a horizontal surface or a wall with plenty of support, rather than hanging.

None of the manufacturers in our review publish the suction cup’s pull strength—how much it actually holds. Diameter and weight are therefore the only figures you can compare.

The shower is the most common place for a suction cup dildo, because tile and glass are ideal surfaces. A dildo without electronics can handle water without any problem—a solid silicone or PVC body has no openings to seal. Therefore, manufacturers of manual dildos rarely publish any IP rating, since it applies to enclosures for electrical equipment.

Two things make the shower more difficult than it looks. Soap and shampoo leave a film on both the wall and the cup that lets air in, and water that runs straight over the edge can dissolve the attachment. Choose a spot where the jet doesn’t hit the suction cup directly, and rinse the wall before you attach the dildo.

Lubricant is the other question. Water quickly rinses away water-based lubricant. Silicone-based lasts longer in water but should not be used on silicone toys, and it makes the floor slippery. More about that in which lubricant should you choose and in the guide about waterproof sex toys.

Often, but not always. Most harnesses hold the dildo with an O-ring that the dildo’s base is pressed through. Then the base needs to be wider than the ring, and the shaft just above the base narrower than the ring. A suction cup often works as such a base, and that’s why many manufacturers list their suction cup dildos as harness-compatible.

The important thing is that the manufacturer actually says so.King Cock Elite 20 cmIt is stated to work with most traditional harnesses and with the manufacturer’s own harness system.Ravager Rippled TentacleIt has a wide, flanged base with a suction cup that the manufacturer states is harness-compatible.Mythology Kuno UtopiaIt is stated to fit the manufacturer’s own harness.

The measurement you most often miss is the neck diameter—how thick the shaft is just above the base. King Cock Elite doesn’t publish it, and that makes it harder to know whether a specific O-ring will fit. Adjustable rings or harnesses with several ring sizes solve that. More about harnesses and how they sit is in How a strap-on worksand in the comparison of strap-on-modeller.

Suction cup dildos are available in both silicone and PVC, and the difference is bigger than it looks. Silicone is non-porous and can be made completely clean—some silicone models can even be boiled. Silexd states for its The Original model that it can be sterilized by boiling for three minutes. PVC can be cleaned on the surface but cannot be sterilized. King Cock 15 cm and King Cock 23 cm are made of PVC, and the manufacturer does not publish any phthalate declaration for them.

Silicone requires a water-based lubricant, because silicone-based lubricants can damage the surface. This applies to the entire product, including the suction cup. A double-density dildo—firm core, softer surface—often has the suction cup molded in the same material as the shaft.

Glass dildos never have a suction cup. They have a flat base or a ball for grip, and they don't attach to anything. If you want glass, read are glass dildos safe?. More about the materials in general can be found in safe materials in sex toys.

The suction cup also shows up on products that aren't regular dildos. Fun Factory Ryde is a so-called grinding dildo with two ridged shafts on a wide base, which can be used with your hands, attached with a suction cup or with a harness. ROMP Jiggle is a thrust vibrator with a suction cup base of 7.4 centimeters, which makes it possible to use it hands-free.

On a motorized product, the suction cup gets an extra job. A regular dildo only needs to withstand what you do with it yourself, while a thrust vibrator sends a force through the base with every thrust. That’s why it needs a larger cup in relation to its size. A thrust vibrator against a hard surface like tile or glass also makes more noise, because the surface amplifies the sound. More about this product type is in thrust vibrator: how it works.

Clean the dildo—also the suction cup—before and after use with lukewarm water and mild soap, and let it dry completely before putting it away. Rinse off all soap from the underside of the cup, both for hygiene and because soap residue reduces the grip the next time. Use a condom if you share the dildo.

Anal use requires a base that is clearly broader than the shaft and a manufacturer that states that the product is made for that. A suction cup can be such a base, but not all of them are. Also keep in mind that a dildo that’s stuck to a wall doesn’t give—take it easy, use plenty of lubricant, and stop if it hurts.

Check the suction cup from time to time. A nick or a crack in the rim means it no longer seals, and a damaged surface on a silicone product becomes harder to keep clean. The full care guide is in How to clean sex toys.

More models with a suction cup can be found in the guides to realistic dildos and fantasy dildos, and in the category of dildos.