Duck lips are called “Ahirukuchi” or “Ahiruguchi” in Japanese (ahiru= duck, kuchi= mouth). Making duck lips is considered kawaii in Japan now, especially among young Japanese girls. In Japan “Ahiruguchi” is defined as upcurved lips with thin upper lip.
The duck lips are a common sight in Japan. Tomochin is widely known for them, and Jurina has been perfecting her technique.
Lately, a wide variety of girls are trying their hand at it, including Yuki and Sasshi.
In an early episode they gave two reasons why the duck lips are considered to be cute.
One of them was that babies have them naturally, and I can't recall the other reason atm.
Examples:
Other AKB48 and other examples:
Some examples of people trying too hard:
http://antiduckface.com/
I included the most well known examples in the poll, but feel free to state a different girl and I will add her to the poll
So, who does it best? Feel free to post pics of your favorite AKB48 related duck lips!