If you don't think every second song is about anal sex then you're not paying close enough attention. Basically every hook in pop music ever can be construed to mean anal sex. It doesn't mean that they are actually about anal sex, it just means that we, as a society, are very, very immature. Or maybe I am.
A risk factor is something that increases the risk of developing cancer. It could be a behaviour, substance or condition. Most cancers are the result of many risk factors.