Angolans serving in the national army have been taking part in an unusual training drill, caught on film.
"Condom Commando" - educating troops in HIV prevention
In between oiling their AK-47s, they have been using bananas as a model for what to do with a condom.
The doctor in charge, Major Andre Chimuco says "many had never seen a condom before, far less used one".
The major's work features in a new documentary called Condom Commando which has just been shown in London for World Condom Day.
According to Unicef, barely 3.9% of Angola's nine million population is HIV positive - but it has all the high risk factors associated with HIV prevalence.
There is just one hospital in the entire country where anti-retroviral treatment is available to people living with the virus.
Dr Chimuco told the BBC's Network Africa programme that he was nervous at first about how the troops were going to react to the lessons: "sitting with other men and using a banana to practice putting on a condom is not what they are used to".
Up to now Angola has not seen the rate of HIV prevalence common elsewhere in southern Africa.
ANGOLA'S HIV RISK FACTORS
70% are aged under 24 years
50% have no schooling
70% are mothers by the age of 20
Largely, it is thought, because the 27-year civil war kept it relatively shut off from the outside world.
However in the five years since the war ended, infection rates have been creeping up.
As soldiers fraternise more and more with the civilian population, it is hoped that enlisting the army in the fight against HIV/Aids will keep both young men and their partners safe.