My first interview took place in Sienna's comfortable family room in an upper-class Washington suburb, where tall windows gave onto a backyard of dark greens and dusky golds and bathed us in light of a late summer afternoon. Her mother, Beth, had prepared herbal tea and a plate of sweets and sat in the armchair across the coffee table from me.    Sienna, in low-rider jeans and a white knit top that showed off her evenly tanned complexion, sank easily into a couch between us. After a few minutes of small talk, I asked Sienna to explain what hooking up meant to her and her friends. She pulled no punches.    "Well, first you give a guy head," she said casually, "and then you decide if you like him and he decides if he likes you."    Beth, who had heard this explanation before, looked me straight in the eyes. "Can you believe this?" she asked softly. She picked up the plate on the coffee table. "Would you like a cookie?" (from Section Two: What It Looks Like, What It Feels Like; p. 64) ~    At 2 a.m. Saturday morning, as Nicole headed for her college sorority house after a night of bar-hopping, she got a “U Busy?” call – in plain English, a solicitation - on her cell phone. “Why don’t we meet up?” James asked. She changed direction, walked to his fraternity. They had sex and fell asleep. Several hours later, as she prepared to leave, he asked her, “What do we do about this?” She stuffed her clothes into a big purse, pulled on some blue flannel sleep pants he offered and a North Face jacket. “We do nothing,” she said. “I got what I wanted.” Then she walked back to her sorority house. A few days later, she tossed his pants in the trash. (from Section Two: What It Looks Like, What It Feels Like; p. 105)