The practice is more of a gentlemen’s agreement where friends can have sex with each others’ wives with no strings attached.
Swinging with an African tribal touch? Or “rape”, as some critics see it.
The wives have little say in the matter, according to those who denounce the custom as both abusive and risky in a country with one of the world’s highest HIV/Aids rates.
But the Ovahimba and Ovazemba tribes, based mainly in this southern African country’s arid north, contend their age-old custom strengthens friendships and prevents promiscuity.
“It’s a culture that gives us unity and friendship,” said Mr Kazeongere Tjeundo, a lawmaker and deputy president of the opposition Democratic Turnhalle Alliance of Namibia.
“It’s up to you to choose [among] your mates who you like the most … to allow him to sleep with your wife,” said Mr Tjeundo, a member of the Ovahimba ethnic group.
Concerned that HIV/Aids could be used as an excuse to stop the ancient tradition, he and others are suggesting regulations be adopted to ensure “good practice”.
Mr Tjeundo said he plans to propose a wife-swapping law, following a November legislative poll when he is tipped for re-election.
Known as okujepisa omukazendu – which loosely means “offering a wife to a guest” – the practice is little known outside these reclusive communities, whose population is estimated at 86 000.
Mainly found in the north-western Kunene region near the Angolan border, the communities are largely isolated from the rest of the country. They have resisted the trappings of modern life, keep livestock, live off the land and practice ancestral worship.