Hollow Strap-ons

A hollow strap-on combines the principle of a strap-on dildo with a hollow interior into which the penis can be inserted. This allows this type of strap-on to be used, among other things, to add extra length or girth during penetration. A hollow strap-on dildo can also be a solution when an erection isn’t firm enough for penetration, but you still want to enjoy penetrative sex together.

Hollow strap-ons are available in various lengths, diameters, and designs. Some models are worn with a harness around the body, while other systems are secured in different ways. Which design is right for you therefore depends not only on the dildo’s external dimensions, but also on the internal length and diameter into which the penis is inserted.

Would you like to explore other types of strap-ons? In our main collection Strap-ons & Strap-On Dildos, you’ll find complete sets, separate harnesses, strapless models, briefs, and interchangeable dildos, among other items.

What is a hollow strap-on?

A hollow strap-on dildo is a dildo with an opening at the back into which the penis can be inserted. The outer part then functions as the penetrating dildo. In English, these toys are often referred to as hollow strap-on or hollow strap-on dildo.

Unlike a traditional strap-on, where a solid dildo is worn in front of the body, with a hollow model, the penis is inserted into the dildo. This allows the body’s movements to be transferred directly to the hollow strap-on dildo.

Depending on the model, the dildo is secured to the body with a harness, straps, or another fastening system. Therefore, always check the product description: the term “hollow strap-on” primarily describes the dildo itself and does not necessarily refer to one specific type of fastening.

Hollow Strap-On Dildo as a Penis Extender

A common reason for using a hollow strap-on dildo is to add length to the penis. The penis is inserted into the hollow shaft, while the outer part of the dildo extends further forward.

For this reason, some models are also described as a penis extender with a harness, strap-on penis extender, or hollow penis extender. How much extra length a particular model actually adds depends on its internal and external dimensions.

So don’t just look at the total length of the dildo. For example, a 20-cm model, a large portion of which is filled by the penis, obviously does not automatically add 20 cm to the penetration length. The internal length is just as important in determining what a model actually does.

More girth with a hollow strap-on

In addition to extra length, a hollow dildo can also provide extra thickness or girth. After all, the outer diameter of the strap-on is larger than the penis inside it.

If your main goal is to create more girth, look at the outer diameter or circumference of the dildo. Keep in mind the experience and preferences of the receiving partner. A significantly thicker dildo can feel much more intense than a few extra centimeters in length.

So here, too, bigger isn’t automatically better. The ideal size is the one that you both actually enjoy using.

Hollow Strap-On for Erectile Problems

A hollow strap-on for erectile dysfunction can be a good option when vaginal or anal penetration with the penis is temporarily or chronically difficult because an erection isn’t firm enough. Because the penis is inserted into a hollow dildo and the dildo is supported by the harness, the penetrating motion doesn’t necessarily require the same level of firmness as penetration with just the penis.

This can also make a hollow strap-on an attractive option for couples who want to continue experiencing penetration when an erection isn’t guaranteed.

Of course, a hollow strap-on does not address the underlying cause of erectile dysfunction. If erectile dysfunction occurs regularly or is a cause for concern, it’s wise to discuss it with a doctor. As a sex toy, a hollow strap-on can simply offer an alternative way to experience penetration together.

Hollow Strap-Ons for a Flaccid Penis

People also specifically search for a strap-on for a flaccid penis. Whether a particular hollow model is suitable for this depends heavily on its construction.

With some designs, the penis does not need to be fully erect to be worn inside the hollow dildo. The harness or fastening system then ensures that the dildo stays in place during movement.

Check the individual product description to confirm whether it’s actually suitable for use without a full erection. The inner diameter, flexibility, and the way the dildo is held against the body can vary significantly from model to model.

Hollow strap-on with harness

A hollow strap-on with harness is secured to the body with straps around the hips or waist. The harness helps prevent the dildo from sliding forward during penetration and gives the wearer more control over movement.

The construction of the harness varies by product. Some hollow strap-ons come as a complete system, while other models allow for the use of a separate, compatible harness.

If you’re specifically looking for a separate harness, check out our collection of Strap-On Harnesses. Always make sure the harness you choose is actually compatible with the hollow dildo you plan to use with it. A standard O-ring harness and a hollow dildo aren’t automatically compatible.

What size hollow strap-on do you need?

When choosing a hollow strap-on, you actually need to consider two sizes at once: the internal size for the wearer and the external size for the receiving partner.

So keep this in mind: Internal measurements are often overlooked, yet they’re precisely what determine whether the dildo fits comfortably around the penis. An impressive exterior is of little value if the interior has decided you’re not allowed inside.

Internal diameter: the available width for the penis inside the hollow shaft.

Internal length: how much space is available inside the dildo for the penis.

External diameter or circumference: largely determines how thick the dildo feels during penetration.

Insertable length: the portion of the dildo that can actually be used for penetration.Total length: the toy’s full external dimensions.

How tight should a hollow dildo be?

A hollow dildo should provide enough space to comfortably insert the penis into the opening. An inner diameter that’s too small can cause uncomfortable pressure, while a very spacious interior may result in less direct contact and support.

Keep in mind that materials can stretch differently. A flexible material may conform differently around the penis than a stiffer design. Therefore, in addition to the specified measurements, also consider the material and the product-specific instructions.

If necessary, apply a small amount of suitable lubricant to the inside to make insertion more comfortable. With some designs, however, too much lubricant can actually cause the penis to slip more easily inside the hollow shaft.

Hollow strap-on for vaginal penetration

A hollow strap-on for vaginal penetration can be used when you want to add extra length or girth, or when penetration with just the penis is difficult.

Pay special attention to the dildo’s external dimensions and choose a size that is comfortable for the receiving partner. The ability to wear a significantly larger dildo does not, of course, mean you have to take full advantage of that capability right away.

Use plenty of suitable lubricant when needed and start slowly, especially if the hollow strap-on is longer or thicker than what you normally use.

Hollow strap-on for anal penetration

Depending on its shape and design, a hollow strap-on can also be used for anal penetration. Always check whether the specific product is suitable for this purpose.

When using it anally, taking it slow and using plenty of lube are especially important. The anus does not produce its own natural lubrication. Especially if the receiving partner has little experience, be sure to choose a size that can be inserted easily and with control.

Do not switch a dildo from anal to vaginal use during the same session without thorough cleaning. A condom over the dildo can make cleaning and safe switching between partners or uses easier; use a new condom for each switch.

Hollow Strap-On vs. Regular Strap-On

The main difference between a hollow strap-on and a traditional strap-on lies in the dildo’s construction. A regular strap-on typically uses a solid dildo worn in front of the body. With a hollow strap-on, the penis is inserted into the dildo.

As a result, the two systems can be chosen for different purposes. A traditional strap-on, for example, is suitable when the wearer wants to wear a dildo independently of a penis. A hollow model, on the other hand, can be a good choice when you want the penis to be part of the system and, for example, want to add extra length or girth.

If you’d like to compare the different systems side by side, you’ll find all the various types clearly organized together in our main collection Strap-ons & Strap-On Dildos.

Cleaning a Hollow Strap-On

With a hollow dildo, the inside requires extra attention during cleaning. After all, the penis comes into direct contact with it, and bodily fluids and lubricant can accumulate there.

Clean both the inside and outside according to the care instructions for the specific material. Use a suitable toy cleaner or another cleaning method recommended by the manufacturer.

Be sure to let the hollow interior dry completely before storing the dildo. Moisture left behind in a sealed cavity isn’t exactly the souvenir you want to keep from your previous session.

If the dildo can be removed from the harness, clean the dildo and harness separately. The harness itself must be maintained according to the instructions for the material used.

What should you look for when buying a hollow strap-on?

If you want to buy a hollow strap-on, look beyond just the external dimensions. Check the following, among other things: It’s especially the combination of internal and external dimensions that makes a hollow strap-on different from a regular dildo. After all, it has to fit on both ends: comfortably around the penis and pleasantly for the person being penetrated.

• the internal length of the hollow shaft;
• the internal diameter;
• the total and insertable length;
• the external diameter or circumference;
• the material and flexibility;
• the attachment system used;
• whether a harness is included;
• the adjustment range if a harness is part of the product;
• whether the model is suitable for use without a full erection;
• the desired application, such as extra length, extra thickness, or support during penetration.

Frequently Asked Questions About Hollow Strap-Ons

What is a hollow strap-on?

A hollow strap-on is a strap-on dildo with an opening into which the penis can be inserted. The outer surface of the dildo is then used for penetration. Depending on the model, the dildo is worn with a harness or other attachment system.

Can a hollow strap-on be used as a penis extender?

Yes. Many hollow strap-ons can add extra length and/or girth. How much extra length a particular model actually provides depends, among other things, on the total length and the internal length of the dildo.

Can I use a hollow strap-on without a full erection?

With some models, this is possible. A harness or other attachment system can support the dildo even when the penis itself isn’t fully erect. Always check the product information, as suitability varies by model.

Do you always need a harness for a hollow strap-on?

Not necessarily. The way a hollow dildo is worn varies by design. Some models come with or are used with a harness, while others have a different attachment system. Therefore, always check the product description.

How do I choose the size of a hollow strap-on?

Consider both the internal and external dimensions. The internal diameter and length must be suitable for the wearer’s penis, while the external diameter and insertable length should match the receiving partner’s preferences and experience.

Extra length, girth, or support

A hollow strap-on offers possibilities that a regular solid strap-on dildo does not. The penis is worn inside the toy, while the outer part is used for penetration. Depending on the model you choose, this allows you to create extra length or girth or to enable penetration even when an erection is less firm.

When making your choice, pay particular attention to both the internal and external dimensions, as well as how the model attaches to the body. Want to compare other strap-on systems? Check out our complete collection of Strap-ons & Strap-On Dildos. If you’re specifically looking for a separate harness, go to the Strap-On Harnesses.