The High-Tech Pillow Guide: How to Use Your ARC-Shape, Adjustable, and Cooling Pillow

Modern pillows are no longer simple bags of fluff. They are “sleep systems” with complex engineering: ergonomic ARC-shapes, zippered liners for adjustable fill, and dual-sided cooling fabrics. But as thousands of user reviews show, these high-tech features can be confusing, leading to a frustrating experience.

A pillow like the KHHMNB (2023 Upgrade) Side Sleeper Pillow, a popular model with over 1,500 ratings, is a perfect case study. It’s packed with features, but user reviews reveal three core frustrations:
1. “My head slides off the pillow!”
2. “It’s way too hard… then I take fill out, and there’s no support.”
3. “The ‘cooling’ effect only works if you don’t use a pillowcase.”

The good news? These are not product defects. They are user manual failures. You own a sophisticated tool, but you’re missing the instructions. This is the guide.

1. The ARC-Shape: You’re Probably Using It Backwards

This is the most common mistake. A user with a “unique ARC design” pillow reports, “The only problem is when used on the curved side, my head slides off the pillow!”

The Problem: You are placing the “ARC” under your neck.
The Solution: The “unique ARC design” is not for your neck. It is a shoulder cutout.

This pillow is “specially designed for neck and shoulder pain” in side sleepers. The ergonomic curve conforms to your shoulder, allowing it to nestle under the pillow. This lets your head rest on the flat, supportive part of the pillow while your neck remains in “correct alignment” with your spine.

If your head is “sliding off,” flip the pillow 180 degrees. The curve goes against your shoulder, not your headboard.

2. The Adjustable Fill: “Too Hard” vs. “Too Flat”

The second major complaint is the “Goldilocks” problem. “This pillow is so hard,” one user writes. “I took out some of the stuffing… not as much support… put the stuffing back… now it’s way too hard again hoping I can find a happy medium.”

The Problem: Shredded memory foam ships highly compressed. The factory “overstuffs” the pillow to allow for adjustment. Your “out-of-the-box” feel is “Extra Firm.”
The Solution: You are not removing enough foam.

A 5-star reviewer, “CARL E. PAPAJ,” unlocked the secret: “It comes in set of 2 very full… for me, I was able to make another pillow with the filler that I removed!“

You are meant to remove a lot of foam—perhaps 1/3 of the total volume—to get to a “medium” or “soft” feel.
1. Unzip the outer cover and the inner liner.
2. Aggressively break up the clumped foam with your hands.
3. Remove handfuls of foam into a separate bag (you now have a free travel pillow).
4. Do not throw it away. “It took me a couple nights of adjusting the fill,” wrote one user. You must experiment by removing more and more until you find your “perfect comfort level.”

3. The Cooling Cover: The “No Pillowcase” Problem

The third frustration is from user “Ramenking1985”: “The ‘cooling’ effect works, but only if you don’t use a pillowcase… there are no pillowcases that fit this pillow properly.”

This user is 100% correct, and it is an intentional design.

The Problem: You are trying to put a pillowcase over a pillowcase.
The Solution: The included “double-sided” cover is the pillowcase.

This pillow’s “removable and machine washable” cover is a high-performance, dual-sided fabric: * Side 1 (“Cooling Ice Silk”): This fabric works through conduction. It must touch your skin to pull heat away. A cotton pillowcase insulates it, “blocking the cooling feeling.” * Side 2 (“Soft Viscose from Bamboo”): This fabric works through breathability. It’s a soft, moisture-wicking side for “cold winter nights.”

You are not supposed to find a pillowcase that fits the ARC shape. You are meant to sleep directly on the cover and wash it just like you would any other pillowcase.

Conclusion: A Sleep System That Needs a Driver

A high-tech pillow like this is a “sleep system,” not a simple cushion. It requires about 10 minutes of “setup” to match your body.
1. Position the ARC curve at your shoulder, not your neck.
2. Adjust the fill by removing a lot of it, not just a little.
3. Use the included washable cover as your actual pillowcase to feel the cooling.

Once you “find the happy medium,” as one 5-star reviewer said, you “will buy more.”