Just don't. Seriously. Just don't ever do it. Nair should only be used on your legs. A girlfriend of mine uses it on her hoohah, but I tried that and let's just say, it should not be done.
I was in middle school when I slabbed on some Nair on my underarms for the first and last time. I had used it on my legs and was fairly comfortable with the product. After about two minutes, my underarms began to burn. I immediately washed off the Nair and noticed tears in my skin. "DID THE NAIR JUST EAT AWAY MY SKIN?!?!" I thought. I screamed and my mom came rushing into the bathroom. I told her what I did and that my underarms felt like they were on fire. Her being a Nurse confirmed that the Nair burned off a layer of skin in the crevices of my armpits. For about a week I couldn't wear deodorant—this was my pre-Certain Dri days—and I had to put on Gold Bond Powder under my arms to heal the burn. From that day on I vowed I would never use Nair again. And... I haven't. Well, except for this one time I used it on my eyebrows. I couldn't resist. My mom loves Nair and it just lies around the house like a book.
The best thing about being young is that you don't really know the world of beauty too well and you are willing to do anything to achieve your result. I'll check Nair off my list as something I did and will never do again. What was your experience like with Nair?