The singular of panties

Is 'panty.'
According to this Victoria's Secret postcard I got promising me $5 any bra and a 'free panty.'

So 'member folks don't say: "What color panties are you wearing???"
Say "What color panty are you wearing?"
Or: "Can I take off your panties?" Should actually be: "May I remove your panty?" (Unless you want to be corrected and you don't, now do you?)

However, do not apply this rule to 'socks.' Do not say "I am wearing a pair of red sock." Or: What color sock are you wearing?

OK. There are sound grammatical reasons 'socks' are different. But I cannot say the same for 'pants.'

Do not show yourself to be a lingerie novice! Give up the word 'panties' for anything but more than one panty or be laughed out of town by those in the know.

By the way do you know Victoria's Secret?
A: She dresses like a slut!