Riding the Pulse — Sam Cheever

Marissa O'Neill and Jurden Bailey share a past they don't remember, though it's haunted their dreams for a decade. In their teens, they encountered something powerful in a cave in Mexico, and it changed them forever. But it isn't until they meet again, years later, that they realize just how much they've changed.

Suddenly they have powers -- super powers -- and they don't know how they're supposed to use them or why they have them. All they know is that sex seems to trigger the power and enhance it. And that's one trigger they're happy to explore.

But something alien and terrifying is trying to kill them, and it won't give up until it gets what they don't even know they have -- the single remaining object that can tie an advanced, alien race to much of Earth's history.

If only Rissa wasn't so distracted by the things Jurden's vibrating finger can do!