What do the Na'vi do to mate?

Answer 1

The Na'vi have a queue, a bundle of neural fibers that extend down from their skull, covered with hair, almost like a long pony-tail. The Na'vi use these fibers to neurally join with certain animals that possess a similar neural bundle and create a bond. To the Na'vi, this bonding is called tsahaylu.

Answer 2

The Na'vi are a very spiritual people and may take a long time to find a mate, but when they do, they mate for life. Physically, Na'vi mating practices are not unlike human ones. On a deeper level, Na'vi mates will join queues, or neural fiber bundles, with each other, creating a lifelong emotional bond (the Na'vi word for this bond is Tsahaylu).