So I'm looking for a book that I read when I was a teenager (around 2009). The book is most definitely fantasy. The book was around an inch and a half thick, with a hard cover, there was a picture on the front in color, but I don't remember exactly what it was. It would have been 25-30 hours worth of reading.
What I remember from the book is the protagonist is a woman, early 20s or so, who has some magical ability to shape shift into animals (Shape shifting never kept your clothes, some awkward scene's happened because of nakedness). One scene, she was riding a female dragon and a male dragon caught up with them and started trying to mate while flying, so the woman had to jump off the dragon or be crushed.
I also remember a male character with a staff, who was seen as an older brother, protector kind of person; And a younger girl who pulled a mental trick of making the thoughts at the forefront of her mind ones that a tree would have, so that she could hide from people looking for her. She was also able to shift her shape into that of a tree.