A strap on dildo is any dildo you can wear in a harness, so one partner can penetrate the other hands-free. The harness gets most of the attention, but the toy itself decides how the experience feels: its base, size, material and firmness. This guide explains the main types, how to pick one that fits your harness and your partner, how to get started, and how to keep it clean and safe.
The short version: For a first strap-on, choose a body-safe silicone dildo with a wide, flat base that fits your harness ring, about 5 to 6 inches long and no wider than 1.5 inches. Use plenty of water-based lube, start slowly, and let the person being penetrated set the pace.
In this guide
- What it is
- Types compared
- The base and the harness
- Size
- Materials
- How to choose
- First time
- Safety and cleaning
- From the Red Pleasures shelf
- FAQ
What is a strap on dildo?
It is a dildo held against the wearer's pelvis by a harness. Planned Parenthood describes harnesses as "garments that hold a packer, dildo, or other sex toy against your body" (Planned Parenthood).
People of every gender and orientation use them. Couples use them for pegging, for penetration when one partner has no penis, or to add variety. Some wearers enjoy the feeling of the base pressing against the clitoris or pubic bone. Others like the role, the confidence or the closeness.
You will see the toy sold as a strap-on dildo, a strapon dildo or a harness-compatible dildo. Some are sold alone, and some come as a set with a harness. Our strap-on harness guide covers the straps themselves.
Types of strap-on dildos compared
There are five main styles. Most beginners start with a plain harness-compatible toy, because it works with almost any harness and is easy to swap later.
| Type | How it is worn | Good for | Trade-off |
|---|---|---|---|
| Harness-compatible | A flared base sits behind the harness ring | First-timers; swapping sizes | Needs a separate harness |
| Hollow | Worn over a penis, usually with its own straps | Partners with erectile changes; extra size | Less sensation for the wearer |
| Double-ended | One end goes inside the wearer, the other faces out | Wearers who want to be penetrated too | Harder to fit and control |
| Strapless | A bulb held inside the wearer, no straps | Experienced users who want closeness | Takes practice and pelvic strength |
| Vibrating | A motor in the shaft or base, sometimes app-controlled | Adding sensation for one or both partners | Pricier; needs charging |
Autostraddle's buying guide notes that a double-ended dildo can work in a compatible harness, so the wearer is penetrated too (Autostraddle). Strapless styles are covered in our strapless strap-on guide.
Why the base matters most
A toy only works in a harness if it has a wide, flared base. The base sits behind the harness's O-ring, so the ring holds it steady and stops it pushing back through.
Check three things before you buy. First, the listing should say "harness compatible" or show a clear flange. Second, the shaft just above the base must fit through your ring snugly. Too loose and the toy flops; too tight and it will not go through. Third, a flat base is more comfortable against the wearer's body than a bulky one.
Many harnesses come with interchangeable rings, so one strap can take several sizes. If yours has a fixed ring, take its measurement to the shop with you. Suction-cup bases often fit too, as long as the cup is wider than the ring. Our suction cup dildo guide explains how those bases work.
What size should a strap-on dildo be?
Start smaller than you think. For most first-timers, about 5 to 6 inches insertable and no wider than about 1.5 inches is plenty, especially for anal play.
Real anatomy is a useful yardstick. A review in BJU International by Veale and colleagues pooled measurements from up to 15,521 men. It found an average erect length of 13.12 cm, about 5.2 inches, and an average erect circumference of 11.66 cm, which works out to roughly 1.5 inches across (Veale et al., BJU International). Many toys sold as "average" are larger than that.
Remember that a harness changes how depth feels. The base and the wearer's hips mean the full length rarely goes in, but hip movement is less precise than a hand. That is another reason to choose a modest size first.
For pegging, go smaller still. Our pegging for beginners guide walks through sizing up over time.
Materials: what is body-safe?
Choose silicone if you can. It is non-porous, holds its shape in a harness, and cleans easily. Planned Parenthood says "it's best to use one made of a body-safe, non-porous material," because porous materials "can absorb germs that can lead to infections, even if you always wash your toy."
- Silicone: the default choice. Firm silicone gives control; dual-density silicone has a firm core with a softer outer layer that feels more lifelike.
- PVC or "jelly": cheaper and soft. When the Danish Environmental Protection Agency tested sex toys in 2006, it found jelly toys were plasticised PVC with a plasticiser content that "may be very high up to 70%" (Danish EPA). Look for a phthalate-free label, or use a condom over the toy.
- Glass and metal: rare as strap-ons, because they are heavy and rigid in a harness.
Pair silicone with water-based lube. Autostraddle's strap-on guide puts it simply: "any silicone dildo should be used with a water-based lube."
How to choose a strap on dildo
Choose by the person being penetrated first, then by the harness, then by looks. The receiver's comfort decides size and firmness; the harness decides the base.
- Agree on the goal. Vaginal play, anal play and pegging can need different sizes and shapes.
- Pick a size about 5 to 6 inches insertable and up to 1.5 inches wide for a first one.
- Check the base is flared and fits the harness ring snugly.
- Choose firmness. A slightly firm toy is easier to guide; a very floppy one bends in the harness.
- Consider shape. A gentle curve can angle toward the G-spot or prostate; a straight shaft is simpler to control.
- Decide on extras such as vibration or a hollow design only once you know what you both like.
Budget note: a well-made silicone toy usually costs more than a jelly one, but it lasts longer, cleans better and works with any harness you buy later.
Using a strap-on dildo for the first time
Talk first, go slowly, and let the receiver lead. Wearing a strap-on feels unfamiliar, so expect a little fumbling and laugh it off.
- Fit the harness before you get going. Adjust it so the base sits snug and centred over the pubic bone.
- Use plenty of lube on the toy and the receiver, and reapply often.
- Start in a position where the receiver controls depth, such as on top. They can move onto the toy at their own pace.
- Move from the hips, with slow, small strokes. The wearer cannot feel the tip, so check in often.
- Agree on a stop word or signal, and stop straight away if anything hurts.
For anal play, extra care matters. Cleveland Clinic, quoting gastroenterologist Michelle Inkster, MD, PhD, explains that "your anus doesn't create its own lubricant" and that "thin tissue means it can tear easily." It advises you to "start gradually" (Cleveland Clinic).
Safety, sharing and cleaning
Wash the toy after every use, and use a fresh condom whenever it moves between partners or between the anus and vagina. Planned Parenthood is direct on both points.
- Sharing: "Sharing sex toys with other people can spread STDs." Putting condoms on toys "can help keep them clean," but "change condoms before the toy touches another person's genitals."
- Anal to vaginal: "never put a sex toy that's been in an anus into a vagina without washing it or changing the condom first."
- Cleaning: "Wash your sex toys with mild soap and water after you use them." Wash the harness too, following its label.
- Storage: keep silicone toys apart from each other and from jelly toys, in a pouch or box.
Our toy cleaning guide covers each material step by step.
From the Red Pleasures shelf
We stock two harness-ready toys right now (checked 1 November 2026):
- Curve Toys 7 Inch Glow-in-the-Dark Rainbow Silicone Dildo with Balls ($35.47 CAD): firm yet flexible silicone, 6.5 inches insertable and 1.5 inches at its widest, with a suction cup. The listing says it is harness compatible.
- Dr. Skin 6" Hollow Strap On Dildo with Harness ($56.15 CAD): a hollow, lifelike toy with a stretchy harness that fits hips up to 40 inches, per the listing. It is made of PVC that the listing calls lab-tested and non-porous; it does not mention phthalates, so we would use a condom over it.
Red Pleasures is an Ottawa-based online store with discreet shipping across Canada and the USA. Browse all dildos, or read our types of dildos guide.
FAQ
Can any dildo be used as a strap-on?
No. It needs a wide, flared base that sits behind the harness ring. A toy without a base will slip through or wobble, so check for "harness compatible" on the listing.
What size is best for beginners?
About 5 to 6 inches insertable and no wider than 1.5 inches suits most first-timers. Go smaller for anal play or pegging, and size up only when it feels easy.
Does the wearer feel anything?
The wearer does not feel the shaft, but many enjoy the pressure of the base against the pubic area, and the closeness. Vibrating and double-ended styles add direct sensation.
Is silicone better than PVC?
Yes, for most people. Silicone is non-porous and easy to clean. PVC is cheaper but can contain phthalates, so look for a phthalate-free label or use a condom over it.
What lube should we use?
Water-based lube works with every material and is the safe choice for silicone. Use plenty, and add more whenever the glide starts to drag.
Can we use the same toy for anal and vaginal sex?
Yes, but wash it or change the condom before moving from anal to vaginal use. Planned Parenthood is clear that a toy from the anus should never go straight into a vagina.
How do I keep the toy from wobbling?
Make sure the shaft fits the harness ring snugly and the straps are tight. A smaller ring, a firmer toy or a harness with a stabiliser plate all help.
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