At the begging of Dawn we are introduced to Lilith a woman who has been living in confinement for what seems like many years. She hasn’t been in control of anything besides her own sanity and will to live. Her life seems alien to us, and we soon learn that it was indeed aliens who forced her into this situation.
These aliens soon inform Lilith that they have saved humanity from the brink of self destruction and that she herself could lead the first batch of humans back to establishing their species on earth. This concept is extremely alien to Lilith but not the most alien to Lilith.
The aliens introduce them into their Oankali society. She learns that everything they use has been synthesized from other species: their ship,their tools, and even their own abilities. This is bizarre to Lilith, extremely weird, but in the end not the most alien thing.
The most alienthing to Lilith seems be the aliens gender roles. THE ALIENS MALES AND FEMALES DO NOT HAVE SEX! This is totally bizarre. The Oankali do not seem to even realize the sentiments behind human sex, on page 96 we see how the Oankali have underestimated the human sexual drive in Paul Titus, when she almost rapes and knocks Lilith out.
Sex as an alien concept to the Oankali World that Lilith has been thrust into come to its peak through the relationship between Joe and Lilith. On page 161 we see Nikanj trying to get Lilith and Joe to join in the Oankali version of sex, this type of sex occurs entirely through sensory responses and lacks one of the most important aspects of human sex.