Flirting, poor hygiene: Veteran instructors share some of the yoga class faux pas they could do without.

"People come to yoga to get away from their stress," explains Sandy Blaine, cofounder of the Alameda Yoga Station in Alameda, California, "and it just follows them in the door unless they remember to turn off their phones."

"The worst?" says Seane Corn, creator of the Vinyasa Flow Yoga DVD series. "When students sip on lattes between poses."

"People should look in and check to see if it's okay to enter, so that they don't disrupt the class in progress," suggests Baxter Bell, M.D., yoga teacher, physician, and medical acupuncturist.

"In addition to the obvious safety issue," explains Blaine, "it interferes with the natural flow and rhythm of the breath in practice."

"It's an intimate atmosphere," says Judith Hanson Lasater, president of the California Yoga Teachers Association, "so take a shower before the class if you need to."

"Teachers are left wondering if you're leaving because of scheduling -- or dissatisfaction with the class," says Bell.

Corn explains: "I've seen students literally twist around mid-pose to check out other classmates."

"This disregards the rights of every other student to have a quiet practice," says Bell.

"I've had women come up and tell me at the end of a class full of backbends that they're pregnant," Bell says.

"I can't tell you how much genitalia I've seen in my lifetime," says Corn.