Like if you go to Japan and you have a fetish for Japanese chicks, you'll be like "My god, there's J-girls for Africa here".

Or, if your girlfriend comes back from an overseas trip laden down with ten bags of M&Ms she bought at duty free, you'll be "Woah, M&Ms for Africa."

Presumably derives from some idea of Western excess. When there's too much of something, you can give it away, like a charitable donation, hence "X for Africa."

I've been jabbed