How to choose a strap-on dildo: size, shape and material

By Devon Marsh, Gear writer · Published 3 September 2026 · Updated 3 September 2026

The best first strap-on dildo is body-safe silicone with a flared base, on the smaller side, with a gentle taper. Get the material and the base right, keep the size modest to begin with, and you can always size up later once you know what feels good.

Picking a first strap-on dildo trips people up mostly because they buy on looks or ambition rather than comfort. Three things decide whether a toy works for pegging: a safe material, a flared base, and a size that suits where you are starting from. Get those right and the rest is preference. This is a guide to the types, not a review of branded products.

A flared base is not optional

For harness use, the toy must have a flared base, meaning a wide, flat end that stops it slipping through the O-ring and keeps it secure. The base is also a firm safety rule for any anal toy, harness or not, because it stops the toy travelling too far. A toy without a flared base is not suitable here. Check for one before anything else, and skip anything that lacks it.

Size: smaller than you think

The most common first-time mistake is buying too big. A modest size is far more comfortable, far easier to warm up to, and much more likely to lead to a good experience you want to repeat. Look at the insertable length and, more importantly, the girth, since width is felt more than length. If you are unsure, choose the smaller option. You can always size up later once your body is used to it, and many people find they never feel the need to.

A gentle taper, narrower at the tip and wider toward the base, makes entry easier and more comfortable. That shape quietly does a lot of the work of a good warm-up.

Shape and firmness

Shapes range from plain and smooth to more contoured. For a first toy, simple and smooth is easiest to warm up to and to clean. Curved shapes can help reach the prostate at a comfortable angle, which some receivers prefer, though a straight toy works perfectly well too.

Firmness matters as much as shape. A softer, more flexible toy is gentler and more forgiving for beginners. A very firm toy transmits every movement directly and needs more careful, slower handling. Softer is the kinder place to start.

Materials that are safe against skin

Body-safe silicone is the standard to look for. It is non-porous, so it does not soak up fluids and bacteria, and it is easy to clean and gentle on skin. Avoid jelly, PVC, and any toy sold without a clear material label, since porous and unlabelled materials can harbour bacteria and sometimes contain irritating additives. If a seller will not say plainly what a toy is made from, that is your answer.

Non-porous materials also let you sanitise the toy properly, which matters more for anal play than almost anywhere else.

Care and cleaning

Wash the toy with warm water and mild soap before and after every use, and dry it fully before storing. If you share a toy or switch between partners, put a fresh condom on it or clean it thoroughly in between, so nothing gets passed along. Store it somewhere clean and dry, away from toys made of other materials. A well-made silicone toy, looked after, will stay good for years.