"So the baas in Cape Town looks at me," he says in Afrikaans. "And he says you look pretty black for a coloured. Are you sure you aren't a kaffir?" His friends Issac Dokter and Willem Jantjies - who are, like him, black - burst into raucous laughter.
Mr Mocoba, 48, pauses with a stand-up comic's keen sense of timing before explaining how a man with skin as dark as his could possibly pass for a "coloured" (the Karoo's mixed race majority). "Then the baas says, ah, but you do speak great Afrikaans."
Mr Dokter has a different explanation for his passing for coloured in a country where skin tone determined everything. "You can have two white chickens who produce an egg but you cannot guarantee the colour of what grows inside," he says. It was always possible for him to argue that his parents (both black) were coloureds and his darkness was an echo from a distant generation.
Much has been written about the misery of apartheid; less about the dark humour shared by those who had to survive the racial madness; the millions of ordinary people who, while the forces of liberation did battle with the mighty apartheid state still had to raise families and somehow scrape a living.
For Mr Mocoba and his friends, from Murraysburg, in the western Cape, survival meant changing their names and forsaking Xhosa and Sotho for Afrikaans: the language of the coloureds and the white baas. They denied their heritage and sometimes even disowned their families to masquerade as coloureds who were given more employment and education opportunities under apartheid, particularly in the western Cape.
Now the three men, and hundreds of others in the Karoo, are marooned in the new South Africa with IDs bearing Afrikaans surnames and a first language which now closes rather than open doors. They have started a campaign to reclaim their identities. They say they are motivated by emotion. But pragma- tism is also at play in a country where it can now pay to be black.
Mr Dokter, a Karoo community worker, is at the forefront of the campaign which hopes to persuade the government to alter identity documents. His parents are both Sotho and came to the Karoo seeking work. He changed his name from Mesotho to Dokter when he was 14 to gain entry to a mixed race school - far superior to the one for blacks.
The school did not believe he was coloured but his double life had begun and all future bids for education and jobs were made under his new identity. Mr Jantjies (real name Owkes) says the Karoo pastors helped blacks by drawing up false baptism certificates. Somewhere along the way the men say they lost something of themselves.
Like Mr Macoba (changed from the more African Makoba), Mr Dokter sees the funny side of the old system ; the need to disguise his love of pap, the black community's staple diet, and the battle to avoid the sun in an attempt to lighten skin by a few crucial shades. But he is also angry that the system caused him to lose touch with his extended family and fractured his connection with the ancestors, so central to the religious beliefs of blacks.
"The Truth and Reconciliation Commission has been occupied with the violence of the apartheid state - the assaults and the killings - but the administration of the system itself did great harm," he says. "There were many black people around here who became so-called coloureds. I want my old identity back. For me it's entirely emotional... My children must know where they really come from."
But Mr Janjties admits some want to reclaim the past because it is now a positive advantage to be black. "I am black but with my name and my use of Afrikaans employers will think I am a coloured trying to be black."
In the new South Africa obsession with colour and race continues. For some the past caused permanent psychological damage - like the barman at a popular Karoo hotel who complains about being one of eight white people in town, besieged by 250 barbarians (coloureds). He is light-skinned but, whatever he was raised to believe, it is clear that he is in fact coloured.
Ironically the government's attempts to right past wrongs through affirmative action perpetuate the insanity. Mr Dokter claims that he walked into his office recently to find a woman he knew applying for a job.
"She was calling herself Thandi," a popular African name. "But I have know her for years as Lorna. She was claiming to be black but she is quite clearly white!" You can hardly blame the three men for once again doubling up with laughter.Reuse content