ultimatums, threats,pleas, and guilt

My father died early sunday morning after a long battle with prostate cancer. He had smoked for most of my childhood but quit 25 years ago, with the excepition of an occasional hidden, stale kool.  By the time we were each 17 my two sisters and i were smoking with parental permission.  My sister, Merri was the first quitter.  And then she was the second.  She remained a non-smoker until her daughter was about 6 months old and her return may have been related to post partum depression.  My other sister Lauren amazes me....she'll smoke for months at a time and then not at ALL for months.

 We were with him at the moment he took his last breath.  i wanted a cigarette so badly...the harshest judge of my smoking was gone.  but i realized that I am my own accountability.  I quit because as a smoker, my medical prognoses were dire.  But my sisters begged me to help them.  So i gave them an ultimatum.  They quit after all the death rituals, the sitting shiva. About a week.  then i smoke a cigrette from each of them.  in front of them. with them.  Of course i'm bluffing.  But what do i threaten next?