Usman has issues with girls. The teenager is so anxious about his failure to attract any, that he writes a desperate letter to a woman he has never met.
"Dear Sissy Aminata," it reads. "My problem is this: I know many girls but none of them will make love with me. I am thinking about going to see a jujuman for love potions for these girls to like me very much."
If Usman follows Sissy Aminata's advice he will think twice about love potions. "Where have you been all this time?" she writes back with a tinge of impatience. "It seems the girls know much more about life and its hazards than you do. You must have heard about Aids, STDs and unwanted pregnancy?"
Sissy Aminata is west Africa's newest agony aunt, dispensing a tough love blend of sympathy, factual information, and no-nonsense advice on everything from painful periods to the risks of becoming infected with HIV.
Sissy doesn't exist in the flesh nor for that matter, does Usman.
The questions and her answers are written by child protection staff from Save the Children, one of the three aid agencies The Independent is supporting in this year's Christmas appeal. Their fictional answer to Virginia Ironside is emerging as a powerful weapon against a pandemic of child abuse and HIV/Aids in one of the world's poorest countries.
Children in Sierra Leone are still coping with the legacy of a brutal 11-year civil war which tore families asunder. Countless children were raped, mutilated, orphaned or forced into armed groups as sex slaves. The bloodshed ended five years ago, but much of the sexual abuse did not. "So many were raped during the war that perhaps people are no longer shocked by rape," says Dieneke Van Der Wijk, director of Save the Children in Sierra Leone.
The conflict also wiped out education for an entire generation, so awareness of sexual health issues is poor. And while around 40 per cent of the population of Sierra Leone is under the age of 14, extreme poverty (75 per cent of the population survive on less than 1 a day) means school is a luxury for many. In the rundown capital Freetown, you see young children out on the streets from dawn to dusk selling everything from toothpicks to peanuts and second-hand shoes.
And if they are easy prey for abusers in the streets, they are not always safe in school either. It's common in some rural areas for teachers to ask pupils to cultivate their vegetable patches in exchange for lessons. In some cases, they have to provide sex.
No wonder then that teenage pregnancy rates are high, sexually transmitted diseases widespread and the country is facing an HIV/Aids timebomb.
Yet for a child to admit they have been raped or abused often carries a stigma. Sex offenders are frequently let off the hook or the case is hushed up. In some cases girls are pushed into marrying their rapists.
What the fictional agony aunt does is to offer a space to children who would otherwise find it too painful or upsetting to discuss their experiences. Not only can they now get hold of facts about sex, but by taking part in the accompanying education groups that Save the Children runs in vulnerable communities, many are gaining the confidence to talk to adults and negotiate their own safety.
In the remote eastern province of Kailahun, an area that suffered unspeakable atrocities during the war, Theresa Kamara was pregnant at 13. She was ignorant then, she says. "Having a baby so young is not a good idea because it leads to so many problems. The father of the child abandoned me. Some girls try to get rid of the baby. One girl I know did that and she died."
Still only 17, Theresa now has the confidence of a TV host as she darts about in a stylish print dress and metallic sandals moderating a group education session for other youngsters at a community centre in a Freetown slum.
The method is simple. Theresa uses the questions sent to Sissy Aminata as a launchpad for discussion. A letter is read out and this serves as a prompt for anyone who feels like it, to articulate their own worries.
The group then examines Sissy Aminata's answer and this is followed by discussion and role play. "We take the examples of these letters and compare them to the things that are bugging us in our lives," Theresa explains.
A tall boy in an Umbro T-shirt puts up his hand. "I am very worried about the Aids," he admits. A girl asks what the difference between HIV and Aids is. Theresa doesn't want to teach though; she wants the young people to talk and to tease out the answers. Hands shoot up and there's a lively debate. Somebody thinks that sharing a blade or a knife is the way to transmit HIV infection. Theresa casts around the room coaxing, "But the big one, the big one?" When somebody offers the right answer, Theresa shakes his hand graciously: "Thank you, brother!"
"Abuse is often kept secret, so children need to be able to talk. Sissy Aminata helps to open minds," says Jeanetta Johnson, Save the Children's health programme manager in Sierra Leone. Staff have been surprised at the enthusiasm of the response and results have been remarkable in some areas, she reports. "One group of kids we know of reported an abusive parent to the police. In another case, a village chief wanted to marry a girl of 14, but the chief's son knew this was unwise and convinced his father not to go ahead."