The Lust Days Bundle. Unprotected Desires, #4

Everyone was aroused all the time... After The Event, there's no turning back. Women are transformed into perfect-bodied, big-breasted, milking nymphomanics and men are turned into virile hyper-studs made for making heirs. The three hot stories of this bundle detail the slices of life in a world utterly transformed by the Mysterious Event and its transformative properties. A road trip turns incredibly sexy when a young man and his girlfriend (and her friends) become unstoppably attracted to each other and succumb to the new primal order.
Two scientists discover that knowledge won't save them from the need to breed. And months after the Event, an especially hyper-virile Hunk adds another gorgeous beauty to his ever-growing harem.and uncovers the secret of what he truly deserves for being so utterly masculine.