A first strap-on purchase involves more decisions than people expect: harness style, dildo size and shape, attachment system, base type, material, and how all of those need to play nicely together. Get any one wrong and the kit is unusable in a way that's both expensive and discouraging. Get them right and you have a setup that lasts years and grows with you.
This is the version of the guide that doesn't assume you know what an O-ring is, doesn't assume you've already chosen a dildo, and doesn't pretend the first session goes perfectly.
Who's this for
Anyone who wants to penetrate a partner without depending on a penis. That's queer couples of multiple configurations, straight couples exploring pegging, partners with erectile dysfunction wanting another option, trans men and non-binary people choosing how to engage in penetrative sex, and people who simply want to be the giving partner sometimes regardless of their usual configuration.
The mechanics are the same across all those contexts. The conversation around it varies, and most couples find that conversation harder than the gear.
The two-piece system
A strap-on is two things: a harness and a dildo. They're sold separately by serious brands and as kits by less-serious ones. The kits often pair the wrong dildo with the wrong harness for the user's body, which is why most experienced users end up buying components separately.
The harness
The wearable part. Holds the dildo in place against the wearer's pelvis. Comes in several styles (below).
The dildo
The penetrating part. Has to have a base compatible with the harness's attachment system.
Almost every fitting problem comes from these two not being matched correctly. Confirm compatibility before checkout.
Harness types
Two-strap (jock-style)
Two leg straps that wrap around each thigh, joining at a front plate. The dildo sits at the front; the rear of the wearer is uncovered. Most stable for active thrusting. Examples: SpareParts Joque, Aslan Jaguar.
Best for: most beginners. The two-strap is the most stable design and the most forgiving of body shape.
Brief-style (panty/boxer harness)
Looks like underwear with an O-ring built in. Easier to put on, looks more like clothing, often more comfortable for longer wear. SpareParts Tomboi is the classic.
Best for: comfort-focused users, people who want the wearable to feel like clothing, gender-affirming use.
One-strap / thong-style
One strap up the back between the buttocks. More minimal coverage. Less stable than two-strap; the central strap can pull during vigorous thrusting. Some users find the strap pleasurable; others find it irritating over time.
Best for: shorter sessions, users who don't mind the trade-off.
Bullet-vibe / wearable-pleasure harnesses
Some harnesses include a pocket for a bullet vibrator on the inside of the front plate, providing clitoral stimulation to the wearer during use. SpareParts Joque and certain Aslan models offer this.
Worth it if pleasure for the wearer matters to you (it should — see below).
Strapless strap-ons
A different category entirely. A double-ended toy with a bulb that the wearer holds inside their vagina via pelvic floor squeeze. No external harness. Examples: Fun Factory Share, Tantus Feeldoe.
Pros: more body-to-body contact, more direct sensation for the wearer. Cons: requires pelvic floor strength to keep in place, slips during vigorous use, takes practice. Often a second purchase rather than a first.
Wearer pleasure (don't skip this)
Most beginner harnesses are designed only to hold the dildo, with no consideration for the wearer's pleasure. This is a design failure that has carried over for decades.
What helps:
- A bullet pocket on the inside of the front plate (clitoral stimulation during thrusting)
- A second dildo internally — some harnesses accommodate a "vag-end" piece for the wearer
- A strapless design where the bulb provides internal stimulation
- The grinding contact of the front plate against the pubic bone — design choices vary widely
If you're buying a harness for someone with a clitoris and the harness has none of these features, the wearer is doing the work for free. That's worth paying attention to.
Dildo selection
This is the second decision and it has its own considerations.
Size
For a first strap-on, smaller than you think. Wearers don't have the proprioception of a penis — they can't feel exactly where they are or how deep they're going. A toy that's average-sized for a partnered cock feels alarming on a first session because the wearer is still learning to pace.
Recommended first sizes: 4-5 inches insertable, 1.25-1.5 inches diameter. You can always go bigger later. You can't make a too-big first purchase smaller.
Shape
- Realistic. Veined, sometimes with testicles. Visual appeal matters to some couples; aesthetics aside, the realistic curve is functional for vaginal use.
- Non-realistic / "fantasy". Smooth, often coloured, sometimes curved. Many people prefer these because they don't carry visual baggage.
- Curved. Designed to hit the G-spot or prostate. Worth the slight premium if the receiving partner enjoys internal stimulation.
Material
Medical-grade silicone, full stop. Avoid jelly, PVC, or "TPE/TPR" without clear material certification. We covered this in the body-safe-toy-labels piece — silicone lasts longer, cleans better, and won't leech anything.
Base
Three common base types:
- Flared base. Standard, fits standard O-ring harnesses, also doubles as a flared-base anal toy on its own. The most flexible choice.
- Vac-U-Lock / suction-cup-with-plug. A specific attachment system used by some harness brands (notably Doc Johnson). Compatible only with Vac-U-Lock harnesses. Avoid unless you're committing to the ecosystem.
- Bulb base (strapless). For strapless designs only.
For most beginners: flared base with a standard O-ring harness. Maximum flexibility.
Sizing the O-ring
O-rings come in different diameters. The dildo's base needs to match. Too small and you can't fit the toy through; too large and the toy slides around or falls out during use.
Most quality harnesses come with three interchangeable rings (small, medium, large). Confirm the harness you're buying has this. Cheap harnesses come with one fixed ring, which limits your dildo choices.
Putting on a harness
Practise with clothes on, alone, before the first session. Learning how the buckles or velcro work in the moment is awkward; learning beforehand removes a layer of friction.
- Fit the harness around the hips/waist with the front plate centred
- Insert the dildo through the O-ring, base flush against the inside of the plate
- Adjust straps so the dildo sits firmly without pulling against your skin painfully
- Test the angle — most beginners' instinct is to angle the dildo too high; level or slightly downward is usually right
If a strap is digging in or the dildo flops, stop and adjust. Sex paused for harness adjustment is fine. Sex with a wrongly fitted harness is uncomfortable for both people.
The first session: what nobody warned you about
- You won't know how deep you are. Watch your partner's face, ask, go shorter than you think.
- The angle takes practice. Most strap-on dildos are slightly upward-curved. Position your hips accordingly.
- You'll get tired. Thrusting is a hip-flexor and core workout that nobody mentioned. Take breaks. Different positions work different muscles.
- Lube generously. The receiving partner needs more lube than they would with body parts — silicone dildos don't add their own lubrication.
- Communication beats performance. "Slower," "deeper," "right there" — the receiving partner is your map. There's no instinct to fall back on.
Positions worth knowing
- Receiver on back, knees up. Easy to control angle, easy to maintain eye contact, gentle starting point.
- Receiver on hands and knees. Better depth, less wearer effort, less face-to-face connection.
- Receiver on top, wearer lying down. Receiver controls everything, wearer can rest, often the most pleasurable for the receiver early on.
- Side-lying. Slow, intimate, gentle.
Cleaning
The dildo: standard silicone toy cleaning — warm water and unscented soap, or boiling for 3 minutes if seamless silicone. The harness: depends on material. Fabric harnesses go in a mesh bag in a cold gentle wash; leather harnesses get wiped with a damp cloth and conditioned occasionally; vegan-leather sits between the two.
Don't store the dildo inserted in the harness — silicone-on-silicone or silicone-on-fabric long-term can degrade. Pull it out before storage.
Budget tiers
- Under R1500: a basic SpareParts or similar harness plus a single Tantus or Vixen dildo. Solid starter.
- R1500-3500: a vibrating-pocket harness plus two dildos in different sizes/shapes. Real flexibility.
- R3500+: custom-fit harness, premium dildos, possibly a strapless option as well. Buy this incrementally over years, not at once.
The bottom line
A first strap-on isn't a single purchase, it's a system. Pick a harness that fits your body and offers some wearer pleasure; pick a dildo that's smaller and simpler than you think; make sure they actually fit each other; practise putting it on before the first session; and budget for awkwardness on the first try.
Done well, this is one of the most flexible additions to a sex life — and one of the most empowering, particularly for partners who've never been on the giving end of penetration before. The first session is rarely the best one. By the third or fourth, most couples land somewhere they didn't know they were missing.
