[Spoilers AFFC] Why does Arianne have these feelings for her uncle?

In AFFC we read the following thoughts from Arianne recalling an outing with Oberyn and Tyene. Sylva asks details of the outing, and Arianne says:

I sat beside the well and pretended that some robber knight had brought me here to have his way with me, she thought, a tall hard man with black eyes and a widow's peak. The memory made her uneasy. "I dreamed," she said, "and when the sun went down I sat cross-legged at my uncle's feet and begged him for a story."

The only character that is repeatedly described with black eyes and a widow's peak is Oberyn. Why does Arianne have sexual feelings towards her uncle? Maybe she isn't thinking literally of her uncle, but someone with that freedom and demeanor. I haven't really seen this discussed.