Oh, to be 12, and profoundly in love with your older brother's best friend. Of all the love songs, is any more beautiful than the sound of him chugging a soda? Is any sight more enticing than his grimy Tevas on the porch?

He is always around, always so polite to your mom, with his husky voice and his thick calves thatched with hair. Note how breezily he ignores you. Sweet agony! Nothing says futility better than the fresh, woodsy scent of his deodorant.

"He was there, like, since basically I was born, and I just always had the hots for him," says Staci Sands, who grew up in Griffin, Ga., in the shadow of a brother nine years older and, of course, his best friend. "His name was Pat. Pat Murphy. It drove him insane. . . . I was like Pat-Pat-Pat-Pat-Pat-Pat!"

The world is filled with Pats. They have seen us in our pajamas. They have seduced us with their soulful eyes and guitar-playing sensibilities. If they aren't a sibling's friend, they are a friend's sibling, or perhaps that second cousin you vacation with every summer. They are the embodiment of what you might call the proximity crush, a fascination not with the inaccessible (pop stars, prom kings), but with what's nearest. We are 13 when we first notice them -- no, we are 11. The proximity crush is an overture to adolescence. It is the crush of peered-through keyholes and creaking floorboards, for which you get all dressed up just to watch TV.

Shanae Simmons, 17, lives in Brackettville, Tex., a tiny town 21/2 hours from San Antonio. In eighth grade she began to notice her best friend's older brother, Levi. He was tall, with tanned skin, beautiful hazel eyes and great comic timing.

"He'd always, like, make farting noises when he walked by," Shanae says.

Shanae was won over. She frequented her friend's house constantly.

Once Levi walked past shirtless and the sight was burned into her memory. ("Don't you realize there's a guest in the house?" Shanae scolded him, hoping her outrage would hide her thrill.)

She collected photos of Levi engaged in mundane activities. There's one of Levi working under his truck, and another of him talking on the phone. She even wrote a song about her feelings, called "The Levi Song," and used to perform it with her little sister doing backup. It had hand gestures. It went:

I know I might be that stupid little girl down the street.

I know that I have extremely large feet.

The great thing about the proximity crush is that we see our beloved in a state of repose. It is like looking upon lions asleep on the veld -- the mystery and danger of the opposite sex is blunted.

If the sibling connection means there is something forbidden about a proximity crush, there is also something quite natural, because already there is intimacy. We have seen the spinach in their teeth. Why fight it?

Sally Brown had a thing for Charlie Brown's friend Linus. A young woman named Rosalynn developed a crush on her best friend's brother; his name was Jimmy Carter. The proximity crush is the subject of romance novels with titles like "Breathless for the Bachelor," and of queries to advice columns. "Dear Sadie: I am very confused about a guy! I am 15, and he's my brother's best friend. . . . He will whisper in my ear or play the foot game . . ."

It works the other way, too. There's no shortage of writings about the mystique of the older woman. Bryan Shoemaker grew up in Fairfax under the thrall of his best friend's sister, who was three years older. She had strawberry blond hair and a wholesome, midwestern-cheerleader look. (At 26, Shoemaker's never gotten past that look. The girls he likes still resemble her.)

"She was like the age of, you know, women," he says. "She could drive and she could do all these grown-up things."

Sometimes, Shoemaker was permitted to sit with her in her pink room and listen to Toad the Wet Sprocket. She would tease him and complain about boys. She was like a cultural translator from the exotic nation of Female.

Did she know he liked her? Did she like him back, even a little? Once in a while, you'll hear a story about a couple -- like Wesley and Leslie Wilson of the Topeka, Kan., area -- formed by a proximity crush. Wes, now 22, was best friends with Leslie's younger brother, Eric, and in elementary school he'd ride the bus home with Eric so they could go to basketball practice together. Leslie was two years older and would make them sandwiches before practice. He thought she was beautiful. He kept asking her out. She kept saying no because he was younger. Wes didn't get her on a date till college, in November of 2003. They married less than six months later. But this seems like a less likely scenario.

More common, no doubt, is the case of Angela Calixte, now 21, beloved by her younger brother's friends. Theirs was a more crude admiration; one said he liked to watch her walk. She regarded them as one might regard fruit flies in the kitchen.

"They were constantly around," says Calixte, who's now married and living in Landover. "Like, they came to see him but they'd be sitting on the couch staring at me, asking me to make a sandwich."

Or, consider the scenario that took hold of Staci Sands and her beloved Pat. For years she thrived on being near him. After sleeping over once, Pat left a T-shirt, which Sands stole from her brother's laundry basket and slept in for years. She volunteered to act as ball girl when her brother and his friends played softball, just so she could be close by.

"They would hit it over the fence and I would run and go get it," says Sands, 32, who now lives in Old Town Alexandria. "I was basically like a slave."

When Sands was 17, Pat came back from some time in the Air Force and "it was like a light went off in his head," Sands says. "He was like, 'Wow. Where did you come from?' "

They started dating, but the setup was weird. There was no mystery; he'd seen her in diapers. They dated for about six months, then broke up.

If there is any permanence to be had, it is in the crush itself. Sands's entire adolescence was formed under Pat's spell. Bryan Shoemaker's feelings persisted for six years. Shanae Simmons still likes Levi, though over the years, she told herself that Levi would never like her.

"I was a spaz," she says.

But the feelings persisted, fueled by her imagination. One time at the movies, Levi reached for a snack and his hand grazed hers. That was big. Another time, Shanae's grandmother bought her a baseball T-shirt with an 82 on the back, and then Shanae discovered that Levi wore the same number on his football helmet. Could that mean something? In eighth grade she made him a valentine out of poster board, decorated with glitter and her grandmother's craft lace. Later, during a secret inspection of his room, she saw that he'd kept it.

He'd kept it.

A crush is pain, Shanae says, but it's magic, too. Sometimes she wants to thank Levi for all he's done for her. It was Levi who taught her that even she, a tomboy, could have "mushy feelings." He was the first boy she ever cried over. He inspired her to write that song, which all her friends once knew by heart:

I might have always dressed like a boy,

Never been no one's little bit of joy.

I may not be your Helen of Troy

Couldn't you have been my boy toy?

Levi has been away for a few years, and Shanae says she's stopped thinking about him as much as she used to. Curiously, though, ever since he started attending Texas Tech, she's developed an interest in going there, too. Recently, when she heard he'd decided to go to aviation school, she began to think she might like to be a pilot.

Proximity.

Proximity's sweet suffering: Linus Van Pelt may be thinking of the Great Pumpkin, but his sister Lucy is probably dreaming about his piano-playing pal, the standoffish Schroeder.Happy ending: Rosalynn Smith, age 18, now Rosalynn Carter, on the day of her 1946 wedding to her best friend's brother Jimmy.