Say: "茄子!"

I tried asking these guys to say "cheese" since it is my Tuesday 10 a.m. freshman Oral English class, but the result was not pretty... so I broke the "no Chinese rule" on this occasion and asked them to say "eggplant" ("Qiézi") in their native tongue. That brought out the pearly-whites! (though they may have been laughing at my attempt at speaking Chinese)