sex unequal to six

It is a joke.I had a language exchange last week.My American friend talked about Chinese movie with me.This movie called " Lust Caution",it is very popular in China,Taiwan and Hong Kong because it is Ang Lee directer direct new movie.This movie has some sex action.My friend asked me "Do you know this movie?"I am very excited reply him "Yes, I know .This movie has some sex."But my spoke tone like six.So he was laugh my tone.It is so funny,he said.Right now,I regret why couldn't studied English better when I was child.My English must become better because I 'll join Toefl test on March.