"Probe" is a catch-all term in this context, covering both anal probes (designed for internal massage, often targeting the prostate) and urethral probes (designed for urethral sounding). They're fundamentally different use cases, but they're often grouped together in one collection because they share similar material and safety requirements. Here's what each type actually is, and how to use them safely if you're considering either.

Anal probes vs urethral probes — what's the difference

Anal probes are smooth, tapered insertion toys designed for anal stimulation, often with a curve or bulb to reach the prostate (if present). They overlap with the broader anal toy category, but tend to be longer, thinner, and smoother than typical butt plugs — more about targeted internal massage than sustained fullness.

Urethral probes (also called sounds or sounding rods) are designed for insertion into the urethra — the tube that carries urine out of the body. This is a niche form of play, and requires a different set of safety considerations than anal play. If you're looking at urethral probes specifically, also read Urethral Sounding: A Beginner's Safety Guide before buying anything.

The rest of this guide covers both types, but sections marked [anal] or [urethral] apply to that category only.

The main types (anal probes)

Straight tapered probes

A simple smooth shaft with a gradual taper from tip to base. The most straightforward design — easy to control, easy to clean, and a reasonable starting point if you're new to anal play generally.

Curved/angled probes

Designed with a bend or curve to reach the prostate (a walnut-sized gland a few inches inside the rectal wall on the front side of the body). If prostate stimulation is your goal, a curve is more effective than a straight shaft — but it's also more difficult to insert comfortably if you're still new to anal play generally.

Beaded or segmented probes

A series of graduated bulbs along the shaft, similar to anal beads but on a rigid core. The sensation comes from the ridges between each segment as they're inserted or removed, rather than from sustained fullness like a plug would provide.

Vibrating anal probes

Add a motor to any of the above designs. Worth considering if you already know you like vibration, but not a necessary starting feature — non-vibrating probes are cheaper, quieter, and simpler to clean.

The main types (urethral probes)

Straight sounds (Hegar or Dittel style)

Smooth metal rods, slightly curved or straight, in graduated diameters. The traditional medical-grade design, and the safest starting point for urethral play. Different diameter sizes are measured in millimetres or French scale (1 Fr = 0.33mm); always start smaller than you think you need.

Beaded or ribbed sounds

Add texture along the shaft for additional sensation. These are an advanced option — only consider them once you're already comfortable with smooth sounds and have a clear sense of what your body tolerates.

Van Buren sounds

A pronounced J-curve design that allows deeper insertion into the bladder. This is a significantly more advanced use case than shallow urethral stimulation, and not something to attempt without specific research and a very gradual progression from straight sounds first.

If you're looking at anything beyond straight smooth sounds, treat it as a second or third purchase after you've already established that urethral play is something your body tolerates safely. The urethra is delicate tissue, and there's no benefit to rushing.

Materials

Stainless steel (surgical-grade 316L or similar) is the safest material for both anal and urethral probes. It's non-porous, fully sterilizable, holds temperature (which some people like — you can warm or cool it under running water before use), and has the smooth, rigid surface that makes insertion easier and safer than softer materials.

Silicone is body-safe for anal probes, and some people prefer the slight give it offers compared to rigid steel. However, silicone is not appropriate for urethral play — the urethra is more delicate than anal tissue, and the surface needs to be completely smooth and sterilizable in a way that only metal or medical-grade glass can guarantee. If you're shopping for urethral sounds specifically, steel is the only material worth considering unless you're working directly with a specialist supplier and know exactly what you're doing.

Avoid anything made from jelly, rubber, or materials without a clear body-safe rating. The mucous membranes involved here absorb whatever they touch, and porous materials can harbor bacteria no matter how thoroughly you think you've cleaned them.

Sizing — start smaller than you think [both]

For anal probes, diameter and insertable length both matter. If this is your first anal toy generally, start small (under 1 inch / 2.5cm diameter, under 4 inches insertable length) even if you're confident — you can always size up, but you can't undo an uncomfortable first experience.

For urethral sounds, diameter is the only dimension that matters, and the difference between sizes is smaller than you'd expect — a 1mm jump in diameter is significant when you're working with such delicate tissue. Most beginners start around 5–6mm (15–18 Fr) for people with penises, or slightly smaller for people with urethras that haven't been dilated before. Never force a sound that doesn't slide in easily — if it's meeting resistance, you need a smaller diameter or more lubricant, not more pressure.

Safety considerations [urethral only]

Urethral play has specific infection and injury risks that don't apply to other forms of toy use:

• Sterilize before every use. Boil stainless steel sounds for 10 minutes, or use a proper medical-grade sterilization method. Soap and water isn't enough here.
• Use sterile lubricant, not regular water-based lube from a shared bottle. Single-use sterile lube packets (the kind sold for medical procedures) are the safest option.
• Never force insertion. If a sound isn't sliding in easily, stop — forcing it can cause tearing, bleeding, or urethral stricture (scarring that narrows the passage permanently).
• Don't share sounds between partners unless they've been fully sterilized between uses, and even then, consider the infection risk carefully.
• Stop immediately if you see blood, feel sharp pain, or have difficulty urinating afterward, and see a doctor if symptoms don't resolve within a few hours.

This isn't a comprehensive safety guide — if you're seriously considering urethral sounding, read Urethral Sounding: A Beginner's Safety Guide in full before attempting anything.

Lubricant [both]

For anal probes, use a thick water-based or silicone-based lubricant (check compatibility with your toy's material first — water-based is universally safe). The anus doesn't self-lubricate, so this isn't optional.

For urethral sounds, use sterile lubricant only — not regular toy lube, not saliva, not anything from a shared bottle. Single-use sterile packets are sold specifically for this purpose and are worth the extra cost.

Cleaning and storage [both]

Stainless steel probes can be boiled for 10 minutes, run through a dishwasher (top rack, no soap), or cleaned with antibacterial toy cleaner and hot water. For urethral sounds specifically, sterilization (not just cleaning) before every use is non-negotiable.

Silicone anal probes should be washed with warm water and antibacterial soap or dedicated toy cleaner after every use. Don't boil silicone unless the manufacturer explicitly says it's safe to do so (some formulations degrade under high heat).

Store probes separately from other toys, ideally in a clean storage pouch or case, to prevent scratching (for metal) or cross-contamination (for any porous material you might have elsewhere in your collection).

Where to start if you're genuinely unsure

For anal probes, a small, smooth, straight or gently curved stainless steel or silicone probe with no motor is the lowest-risk first purchase — it gives you a clear sense of how your body responds to this type of stimulation before you commit to anything larger, textured, or vibrating.

For urethral sounds, a set of graduated stainless steel sounds (Hegar or Dittel style) starting at 5–6mm diameter is the safest entry point — and only attempt it after reading a full safety guide and confirming you understand the infection and injury risks involved.

Browse the full range in Probes. For anal play generally, start with Beginner's Guide to Anal Play: How to Start Safely and Comfortably. For urethral sounding specifically, read Urethral Sounding: A Beginner's Safety Guide before buying anything. For material safety and cleaning, see Safe, Body-Friendly Materials: What to Look for When Buying Adult Toys and How to Clean, Store, and Care for Your Adult Toys the Right Way.