A timer option is added in the config (by default : -1) : when you click on a NPC : (x is the value in the config file)
if x on -1 : you will see the text, and nothing will happen after
if x on more than 0 : you will see the text normally, and x seconds after the first click the next message will be shown. (if you re-click on the NPC while the timer is running, don't worry, the timer will restart with the next message.