I'm saying that race doesn't provide an intrinsic feeling. So, in the context of a racially homogenous society, those white people wouldn't feel "white", because ethnicity provides the separation. To introduce myself and black friend into the scenario is to introduce a different race into the equation. So, that's what would make them aware of their whiteness and my blackness. They would construct their racial identities from there, because it would be a factor that hadn't existed before.

Hopefully, they would be open enough to observe the ethnic differences between us (myself and Tanzanian) and see that blackness isn't a homogenous identity. We would, however, have little say in constructing what it means to be black in that instance. The society of that country would construct our experiences.

Further, our interpretations of those experiences would be shaped by our ethnic differences, b/c being black in Tanzania is different from being black in the US. So, I still think our racial identities are not intrinsically felt, they're shaped by our respective societies.