Four hours and counting should certainly do it. The longest actual mating I've observed was yesterday. Sister Skink, hatched here 2004, shed the previous evening. Little Charlie, hatched here 2008, began the parallel thing as soon as she was introduced into his cage. They were hooked together by 10:30 AM and still an item when I stopped checking at 7:00 PM. This was his first mating with any other Eastern.