since you are from chennai, I suggest u to go to T nagar (saravana stores) there u can find lot of good things. If that's not the case then u can buy in malls. I think u are worried about billing the product, just be brave nobody will ask u for whom u are buying if they ask u can always reply its for my wife or gf like that ?. zivame.com is best for lingerie they have whole lot of stuffs.
