She read an article in a women's pocket-size magazine, called "Sex Is Fun-or Hell." (1.1)
This theme is introduced to the text early. Salinger gets us thinking (and speculating) about Seymour and Muriel's sexual relationship.
He glanced at the girl lying asleep on one of the twin beds. Then he went over to one of the pieces of luggage, opened it, and from under a pile of shorts and undershirts he took out an Ortgies calibre 7.65 automatic. He released the magazine, looked at it, then reinserted it. He cocked the piece. Then he went over and sat down on the unoccupied twin bed, looked at the girl, aimed the pistol, and fired a bullet through his right temple. (1.109)
At this point, the reader either feels bad for suspecting Seymour of pedophilia, or vindicated (if he or she suspects that Seymour killed himself out of guilt for his sexual desires).
"I said he drove very nicely, Mother. Now, please. I asked him to stay close to the white line, and all, and he knew what I meant, and he did. He was even trying not to look at the trees-you could tell. Did Daddy get the car fixed, incidentally?" (1.24)
We can infer from this passage that Seymour, perhaps intentionally, drove a car into a tree. Some readers have posited that this aggression is sexual in nature.
Section II (Seymour on the Beach and in the Hotel)
"Sybil," he said, "you're looking fine. It's good to see you. Tell me about yourself." He reached in front of him and took both of Sybil's ankles in his hands. "I'm Capricorn," he said. "What are you?" (2.26)
Do you think that Seymour's conversation with Sybil borders on the flirtatious?
"I was sitting there, playing. And you were nowhere in sight. And Sharon Lipschutz came over and sat down next to me. I couldn't push her off, could I?"
"Oh, no. No. I couldn't do that," said the young man. "I'll tell you what I did do, though."
"I pretended she was you." (2.30-34)
Seymour's conversation with Sybil alternates between adult flirtation and child-like jokes.
"Sharon Lipschutz said you let her sit on the piano seat with you," Sybil said.
"Next time, push her off," Sybil said. (2.27-37)
Sybil definitely has a harmless crush on Seymour.
The young man suddenly picked up one of Sybil's wet feet, which were drooping over the end of the float, and kissed the arch. (2.92)
This is the point in the story where the reader, if he or she has suspected any sexual motivation on Seymour's part, might re-evaluate. This movement seems to reveal reverence, rather than sexual desire.