I've been trying to find out just how much parafin do you put into the chocolate? Years and years ago, I used to do that, but have forgot how much to use! The parafin seals the chocolate so that it keeps what's inside fresh and does not melt in your hand.
With the peanut butter, I'd be sure to chill the peanut butter balls before dipping it into the chocolate. The fat in the peanut butter may melt a little and get a little gooey.