Rion by Susan Kearney
Back in September, I read Lucan, the first in the Pendragon Legacy series, and loved it, so when I got a chance to read Rion, I couldn't pass it up.
Marisa is Lucan's sister and Rion is his best friend, but I don't think you need to have read the first to enjoy this one.
In this future world, one-tenth of Earth's population are dragonshapers and Marisa is a telepath who is helping them learn to control themselves as dragons. Rion is from the planet Honor, where his people, all dragonshapers, have become enslaved to an evil alien Tribe, the Unari. Only with Marisa's help can Rion organize a revolt and save his people.
It took me a little while to warm up to the book. First off, even though I knew they were both dragonshapers and Marisa always has scales on some parts of her body, during the first sex scene, when "her scales rumbled in wave after wave...