The right first butt plug is 25mm (1 inch) maximum diameter at the widest point. This is significantly smaller than most "starter sets" suggest, and there's good reason: comfort and gradual adaptation matter more than getting to a larger size quickly.
Why 25mm specifically
The anal sphincter is two muscles — the outer (voluntary) and inner (involuntary). Both relax with familiarity, lubricant, and time, not force. Starting too large produces discomfort that the body learns to associate with the activity, making future sessions harder rather than easier.
A 25mm plug:
- Comfortable for the body to accommodate within 5–10 minutes of warmed-up insertion.
- Sits behind the sphincter once seated; the bulb shape keeps it in place without holding.
- Small enough that movement and walking don't produce sustained pressure.
- Capable of producing pleasure without prerequisite tolerance.
The non-negotiable features
Regardless of size, the first plug must have:
- A flared base wider than the plug body — non-negotiable safety feature. The anal cavity creates suction; toys without a flared base can migrate inward. UK A&E departments routinely handle retrieval cases.
- Platinum-cure silicone material — non-porous; sterilisable; lasts for years. Not TPE, not jelly, not "silicone-blend".
- Tapered shape — narrow tip; wider body; flared base. Insertion follows the narrow-to-wide gradient.
- Smooth surface on the body-contact areas — no aggressive texture for a first piece.
UK first-plug picks
At the 25mm starter diameter:
- B-Vibe Novice Plug (£35–£40) — designed specifically for first-time use; tapered shape; flared base; vibrating option available.
- Fun Factory BootyTrainer Small (£30) — German engineering; clean tapered shape; durable.
- Tantus Ryder (£25–£30) — US-made; reliable; platinum-cure silicone.
- Lovehoney Beginners Bum Plug (£15–£20) — entry-level; silicone; reasonable for first-time use.
The progression after the first plug
After 2–4 weeks of comfortable use at 25mm:
- 35mm medium plug. Same materials standard. Usually pairs naturally with the small plug from the same brand (Fun Factory BootyTrainer Medium, B-Vibe Novice Medium).
After several weeks at 35mm:
- 45mm or larger (optional). Most users stop at 35–45mm; sensation and pleasure typically plateau in this range. There's no requirement to escalate.
What to skip
- "Training kits" with 5 or 6 sizes. Three is the right number. Six-piece kits include sizes you won't use or sizes that aren't a sensible progression step.
- Jelly rubber or TPE plugs. Porous; can't be sterilised; the gut bacteria accumulation makes anal use of porous materials specifically unsafe.
- Vibrating plugs as a starter. The vibration distracts from the actual sensation of accommodating the plug; learn the basic shape first.
- Glass or steel plugs as a starter. Beautiful and functional, but the rigid material is less forgiving of angle errors. Wait until you have body familiarity.
- Plugs with aggressive texture (ridges, bumps). For a first piece, smooth is right.
- Anything without a flared base. Mandatory; doesn't matter how good the rest of the design is.
How to use a first plug
- Bathroom break 1–2 hours before — a normal bowel movement clears most of the lower rectum.
- Warm up first — the body needs to be in a relaxed state. Don't start with the plug; have it as a later element.
- Plenty of lubricant — a thick, glycerin-free water-based lube. Apply externally first; pre-warm by holding the bottle in your hand for 30 seconds.
- Slow insertion — narrow tip first; pause whenever there's any tightness; the sphincter relaxes within 30 seconds of stillness.
- Wear time 5–15 minutes for first sessions. Build to longer over weeks.
For the longer protocol, see our detailed guide on how to use a butt plug safely UK.