Have you ever had those moments when you wake up in the middle of the night, thirsty? You're in such a sleepy funk that you can't muster the strength to lift yourself up to fetch a glass of water, even if you know it's in your best interest?

Well, that's how I feel after watching Select Comfort (NASDAQ:SCSS) hose down its guidance for the year in last night's quarterly report.

I mean, I saw this coming. This is what I wrote after rival Tempur-Pedic (NYSE:TPX) posted better-than-expected results last week:

Hooray for Tempur-Pedic. As a Select Comfort shareholder -- and Sleep Number bed owner -- I think I'm going to be sick.

It seems as if the market is willing to reward just one mattress maker at a time. Obviously, the bedding market didn't grow by 22% this past quarter. Retailers like Bed Bath & Beyond (NASDAQ:BBBY), Limited's (NYSE:LTD) Bath & Body Works, and Pier 1 (NYSE:PIR) would be flying high if folks were splurging on home furnishings and feel-good knickknacks. They're not. Tempur-Pedic is in its own cool groove at the moment.

If it's pulling in those kinds of numbers, its premium-mattress rivals are going to come in weak. So I'm braced for the worst when Select Comfort reports next week.

Like a chump, I let my own warning dangle like an inviting glass of water as I catatonically counted down the days to Select Comfort's report.

I guess I deserve what I got. Tempur-Pedic may have grown net sales by 22%, but Select Comfort's top line inched just 3% higher. Earnings took a similar baby step, up to $0.26 a share after last year's $0.25.

"Well, at least Select Comfort is growing," a bull would argue. Let's not even go there. For starters, a massive share buyback is why earnings held up on a per-share basis. Net income actually fell 15% during the period. Don't get too giddy about the top-line growth, either. The company continues to ramp up its outlets, but same-store sales fell by 6%. Healthy online sales (up 30%) and plans to enter new markets (g'day, Australia) aren't enough to offset the weakness that's about to get even worse. Even a stodgy mattress giant like Sealy (NYSE:ZZ) is stealing market share from Select Comfort these days.

The maker of the Sleep Number air-filled mattress says that instead of earning $0.87 to $0.93 per share this year, it's now looking to earn $0.75 to $0.81. Its net sales targets are being slashed as well. In other words, the current quarter is going to be ugly. 

So what am I doing craving water in the middle of the night? With the company unlikely to keep buying back enough shares to offset its bottom-line declines, I should be reaching for a harder drink.

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This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.