How to Choose the Right Strap-On Dildo Size: A Practical Guide

Quick Answer

Start with a strap-on dildo that's about 1 to 1.5 inches in diameter and 5 to 6 inches in insertable length if you're new to penetration. For more experienced users, consider larger girth and length, but always prioritize comfort and harness compatibility. Choose a toy made of body-safe silicone for easy cleaning and long-lasting use.

Choosing the right strap-on dildo size can feel overwhelming with so many options on the market. But the key is to focus on two main factors: the wearer's comfort and the receiver's experience. A good fit means the harness holds the dildo securely, and the size feels pleasurable, not painful.

This guide breaks down what to consider when selecting a strap-on dildo, from length and girth to material and shape. Whether you're a beginner or looking for a larger challenge, these practical tips will help you make an informed choice.

Understand Length and Girth

Length matters for depth, but girth (thickness) often affects comfort more. A longer dildo can hit deeper spots, but if it's too thick, it can cause discomfort. For beginners, a dildo with a diameter around 1 to 1.25 inches is a good starting point. More experienced users might prefer 1.5 inches or more.

Consider the insertable length—the part that actually enters the body. A 5 to 6 inch insertable length is versatile and suitable for most. If you want deeper stimulation, look for 7 to 8 inches, but always use plenty of lube and go slowly. Remember, the base of the dildo needs to be harness-compatible, so check the flange or base size.

• Measure the circumference or diameter of the dildo to know its girth.
• Check the insertable length, not just the total length.
• Look for a flared base if you plan to use it in a harness.

Match the Dildo to the Harness

Not all dildos fit all harnesses. The base of the dildo must be wide enough to stay secure in the O-ring of your harness. Most harnesses come with interchangeable O-rings, but some do not. If you're buying a harness separately, check the ring size and compare it to the dildo's base diameter.

For example, the Curve from Tantus is harness compatible and features a curved shape that can stimulate the G-spot or P-spot. Its smooth, firm silicone is easy to insert and comfortable for both partners. When choosing a dildo for a harness, always verify that the base is flat and flared to prevent it from slipping through the ring.

Also consider the weight of the dildo. Heavier dildos, like the Meat Wave which weighs nearly three pounds, may require a more supportive harness, especially for longer sessions. A cross-strap harness can provide extra stability for larger toys.

• Check the O-ring size of your harness and the base diameter of the dildo.
• For heavier dildos, choose a harness with wider straps or a cross-strap design.
• Always ensure the base is flared to prevent accidental slippage.

Consider the Receiver's Experience

The receiver's comfort is paramount. If they're new to penetration, start with a smaller dildo and gradually increase size as they become more comfortable. Communication is key—check in regularly during play and adjust as needed.

For those who enjoy a fuller feeling, a girthier dildo like the Inner Band Trainer is designed to gradually stretch and fill as it enters. Made of 100% Ultra-Premium soft silicone, it offers a comfortable yet filling experience. If the receiver prefers more texture or a curved shape for targeted stimulation, the Curve or They/Them might be better options.

Remember, lube is your best friend. Use a generous amount of water-based or silicone-based lube to reduce friction and enhance pleasure. Silicone toys are compatible with water-based lube; if you use silicone lube, test it on a small area first to ensure compatibility.

• Start small and build up gradually.
• Communicate with your partner about comfort and pleasure.
• Use plenty of lube to ensure a smooth experience.

Material and Safety

The material of the dildo affects both safety and sensation. Tantus uses 100% Ultra-Premium Silicone, which is body-safe, non-porous, and easy to clean. Silicone is hypoallergenic and can be boiled or washed with soap and water, making it a great choice for hygiene.

Avoid toys made of porous materials like TPR or TPE, as they can harbor bacteria. Always choose silicone or other body-safe materials. The firmness of the silicone also matters: softer silicone is more flexible and comfortable, while firmer silicone provides more intense stimulation. For example, the Hoss Firm is made of firm silicone for high-intensity play, while the Inner Band Trainer uses soft silicone for a gentler stretch.

When cleaning your silicone dildo, use mild soap and warm water or a toy cleaner. You can also boil it for a few minutes to sterilize, but check the manufacturer's instructions first. Proper care ensures your toy lasts longer and remains safe for use.

• Choose 100% silicone for body safety and easy cleaning.
• Softer silicone is more forgiving; firmer silicone offers more pressure.
• Clean your toy before and after each use with soap and water or a toy cleaner.

Decision Rules for Choosing Strap-On Dildo Size

• If you're a beginner: Choose a dildo with a diameter of 1 to 1.25 inches and an insertable length of 5 to 6 inches. Look for soft silicone and a flared base. The Curve is a good option for its smooth shape and moderate size. Start with something that feels comfortable, not challenging.
• If you want more girth: Look for a dildo with a diameter of 1.5 inches or more. The Inner Band Trainer gradually stretches, making it easier to accommodate larger sizes. Ensure your harness can handle the base size. Gradual stretching helps avoid discomfort and injury.
• If you want a larger, more intense toy: Consider a firm, large dildo like the Hoss Firm. This is for advanced users only. You'll need a cross-strap harness for secure use. Be prepared for a high-intensity experience. Only choose this option if you have experience with larger toys.

Strap-On Dildo Options from Tantus

• Curve: The Curve enables people to combine the versatility of harness play with the curved shape for direct G-Spot or P-spot stimulation. Better still, the angle of the Curve makes it ideal for anal or vaginal play, and the smooth, firm silicone makes penetration a joy for everyone. If you or your partner enjoy targeted stimulation, the Curve's shape and firmness can hit the right spots while staying harness-compatible. It's a great mid-size option for those who want a little extra precision.
• They/Them: Introducing They/Them— a harness compatible, 100% Ultra-Premium Soft Silicone dildo that plays amazingly. This is a short, stout dildo that you can use a considerable amount of thrust for a good hard pounding without pounding your cervix or insides. It’s perfect for feeling the girth, and the soft silicone is great to contract the muscles against. For those who want a fuller feeling without deep penetration, They/Them offers a thick but short design that's ideal for intense thrusting without hitting the cervix. Its soft silicone is comfortable and allows for muscle contraction play.
• Inner Band Trainer: This sleek toy was designed to gradually stretch and fill as it enters, a perfect toy for those looking for a larger feel or want to work up to something larger! Made of 100% Ultra-Premium soft silicone, this is a toy for people who demand quality from products they put in their bodies. Harness Compatible: Yes. If you're working up to larger sizes, the Inner Band Trainer's gradual stretch helps you build confidence and comfort. Its soft silicone and harness compatibility make it a versatile training tool for both solo and partner play.
• Hoss Firm: Experience epic, high-intensity play with our firm Tantus Silicone. Hoss is by far Tantus' biggest realistic dildo. Made of 100% Ultra-Premium silicone, this is an advanced toy for people who know what they are doing and demand quality from products they put in their bodies. Harness Compatible: Yes, but only with a cross strap harness. For experienced users seeking a large, firm dildo, the Hoss Firm delivers intense stimulation. Its size and firmness require a cross-strap harness for secure use, so make sure your setup can handle it. This is not a beginner toy.

Best For vs. Not For

Best for

• Beginners who want a comfortable, body-safe dildo for strap-on play.
• Those who prefer a shorter, thicker dildo for girth-focused stimulation without deep penetration.
• Experienced users seeking a large, firm dildo for intense play with a cross-strap harness.

Not for

• People who are new to penetration and prefer a smaller, less intimidating size.
• Those who don't have a harness with a compatible O-ring size for larger bases.
• Anyone looking for a soft, flexible toy when they choose a firm option like Hoss Firm.

Choosing the right strap-on dildo size comes down to understanding your comfort level, the receiver's preferences, and the harness compatibility. Start with a moderate size, communicate openly, and prioritize body-safe materials. With the right fit, strap-on play can be a deeply satisfying experience for everyone involved.