Ladies, what color should I get?!

Ladies, what color should I get?

My bf lost a bet to me in a game of pool and now he has to wear a womans thong. I'm trying to go easy on him by picking something out thats not too feminine looking, but that will still give him the experience of a different material texture and fit from the comfy cotton boxers he always wears. What do you think of this one? And what color should I go for?
Or should I go for a different womans thong? Im trying to get as much feedback as I can so I can make a good choice!

http://www.barenecessities.com/simone-pe...

I agree you should get it in black so if someone sees it they will think he bought it for himself.