How to Choose Your Dildo Size & Size Up: 4 Essentials

Dimensions matter.

Among your top "dildo decisions" before purchasing a new (or first!) toy, size is arguably the most important choice. Because: If you buy a toy that's too big for you to get it in comfortably, then you can't enjoy the toy at all!

Four simple guidelines will help you up-size safely:

1. Choose your size smartly! When sizing up, do not increase more than 0.3-inch diameter between your previous largest toy & your new goal. A soft tape measure is your friend here.
2. Use plenty of lube when inserting the new toy.
3. Always insert slowly, don't shove the dildo in too fast. It's not unusual to need a good 10–15 minutes of warmup, or even more.
4. Listen to your body's pain cues closely, as well as to any other sensation signals. Stopping if you feel real pain is how to avoid fissures & damage from over-stretching!

1. Choose an Appropriately Sized Toy

You gotta know where you're starting out, so you can choose your right size. If you already own dildos or insertable toys, then figure out exactly how large those are! 

If you don't have a dildo now, then you'll want to insert as many fingers as you can, comfortably; and—slowly pulling the out, trying not to expand or contract their width—use those fingers as your metric to judge size by.

A sewing tape measure is so helpful here: either if you can't find the dimensions of your existing toy, or if you're measuring your fingers / your partner's fingers! For only literally a couple bucks, you get a tool that'll give you a close measurement.

All Uberrime dildos and plugs include both insertable diameter and length in the Dimensions section at the end of the description. 

Remember that diameter = the distance across (say, if you measure right-to-left), while circumference = the distance all the way around. Circumference is always larger than diameter.

If you're moving from a dildo you already own and find comfortable, but you know you want a thicker one next: Increase no more than 1" circumference bigger for your new dildo, in general. That's about 0.3 inches diameter step-up.

If your previous comfy toy is already kinda tight, don't go over 0.25" diameter wider for the next.

Super-soft silicones, especially Uberrime's 00-30 Soft & Squishy, may make a toy's maximum diameter feel slightly smaller, if you're comparing the new, soft platinum silicone dildo to a previous harder silicone sex toy. In that case, you might be able to increase up to 0.5" diameter for an 00-30 super-soft dildo—or that increment may still be too big a jump, so it's a risk.

That's why it's important to insert slowly and safely, and learn your personal limits:

2. Lubricant.

First, when you start inserting a bigger silicone sex toy, you should have a favorite good lubricant at hand!

Stretching definitely requires more lube vaginally, than if you're taking a toy that's easy to get in. Lubricant also will smooth any textures on a dildo.

And anally, lubricant is simply a *must* in all cases. The tissue over your anal canal (including the anal sphincter muscles, which keep the rectum closed normally) will not lubricate itself.

3. Go Slow when inserting it.

Patience! Sometimes when you get a new dildo, you just want to stuff it in immediately.

But if you're going bigger, it's smart to take your time.

Slow and gentle insertion will prevent against creating any micro-tears in your skin (epithelium, whether vaginally or anally).

With anal play in particular, go really slow. You're going to be gently probing the hole, teasing your sphincter muscle—which should be pleasurable in itself! Grip the bottom of the toy's base, and push a small amount—less than an inch—inside. If you feel a lot of resistance and tightness, continue teasing with the entry; probing consistently, with shallow insertion. Eventually—whether it takes 3 minutes, or 12 minutes—your hole will begin to actively pull the sex toy inside.

After you reach a new best, stop and give your butt a break for a day or two. If you're moving up 0.5 inches diameter plus, do stretch your anal training out over several weeks. For example, if you're 100% new to anal insertion, and are wanting to reach a thick dildo, the stretching process should take you at least a month, if not more.

Talking about what you feel:

4. Listen to Your Body.

As you slowly insert your new, bigger sex toy: How does the stretching feel?

Safe sizing up and stretching for penetration are impossible *if* you're not actively listening for your body's cues.

With first-time anal / beginner anal sex, a sensation of weirdness is not unusual. It's not necessarily bad, either. It's when the "Hmm, I'm not sure about that" changes to "Ouch, no" that you gotta be aware, and go slower.

A good tip is to avoid extreme stretching (and anal depth play) if you're drunk or altered in any way. It's easier to miss the warning signs, the lesser pain signals, before it's too late.

Any flash of pain is hard signal to stop it. Pause from the penetration for a minute, let your hole rest, and consider whether the pain was caused by 1) penetration going too fast, 2) the toy being too large, 3) not enough lube being used / you've gotten dry, or 4) any other factor.

Limits of Your Stretching

As you progressively size up (going between 0.25" and 0.31" diameter more, with each new step-up in size), you'll sooner or later find you've reached a plateau.

Since you're not a noob at stretching anyone, you'll be able to think about whether you're happy with where you are. Do you want to keep going bigger, or is your largest toy right now perfect-sized for you?

Everyone will have different preferences for maximum girth, and how big they wanna keep going. Many people don't feel a need to become "size royalty"; they may only want to get up to about 2-inches diameter, which is thick but not HUGE. Other folks just love the feeling of being stretched open, and keep on moving up into enormous toys. The latter is more common with one hole than the other:

Vaginal vs. Anal Expansion

Massive anal stretching is more popular than huge vaginal size-fandom, but neither practice is inherently more dangerous as long as you are progressing slowly and stopping whenever you feel pain.

The vagina's depth is naturally limited by the cervix. Now, some women and other folk with vaginas can train to take deeper toys, even (apparently!) reaching over 8-inches insertable depth, whereas median vaginal depth is only about 4.8 inches (when aroused).

So, a generalization about vaginal stretching that's usually but not always true: It is so much easier to girth stretch vaginally, than to expand over 6 inches insertable length (=depth). If you're into vaginal stretching, you're probably going to enjoy thickness. And any extra length in your dildo, can just remain outside the vagina: either lying against your bed or gripped as a handle.

For me: I'm the biggest fan of dildos with 2-inch diameter, and can warm up to about 2.2 inches width within my first 5 minutes of play. Going beyond 2.3 inch diameter becomes more of an exercise, requiring careful stretching. Getting up to 3.8" diameter has been my personal best: a real experience that took days, 3 other smaller toys first, and copious amounts of lube!

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Phallophile Reviews has been goin' strong with a deep love of silicone dildo reviews—all the feel 👐 details!—and composing critical vibrator guides, plus butt plug findings & a multitude of sexy adventures, since 2017.