Consider this a PSA: Don't let your friend do downward dog if you can see her ass through her yoga pants.

Yes, this is a real concern.

According to an FAQ posted on its site, Lululemon is recalling 17% of all women's bottoms in stores–specifically bottoms made from a the retailer's signature luon fabric, a nylon and Lycra spandex blend–because of excessive sheerness.

The retailer wrote:

"The ingredients, weight and longevity qualities of the women's black luon bottoms remain the same but the coverage does not, resulting in a level of sheerness in some of our women's black luon bottoms that fall short of our very high standards."

The issue affects "certain shipments of product received from our factories and available in store on March 1, 2013." Which means if you purchased and wore a pair of Lululemon's stretchy black pants in the past few weeks, you might have shown off a little more than just your flexibility in yoga class, pretty much confirming every yogi's worst nightmare.

The retailer pulled all faulty bottoms this weekend, and is trying to figure out what went wrong and how to fix it. According to a statement, the issue is "not the result of changing manufacturers or quality of ingredients. We are working closely with them to understand what happened during the period this fabric was made." Lululemon will also offer full refunds or exchange to customers who purchased the faulty products.

In the meantime, there'll be a shortage of luon pants in stores and online, which is a big deal–and not just for Lulu addicts. The Wall Street Journal reported last night that Lululemon's stock fell 3.8% and is down another 5.2% in after-hours trading yesterday.

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Photo Credit: Lululemon