No. Are you fucking kidding me? No, I would not fuck my cousin. Would you let your kids fuck your brother's kids? That's fucking wrong, immoral, disgusting, desperate, pathetic, etc. There's 6 billion people in the world. Chances are 5-20 of them are your cousins.
That leaves around 5,999,999,980 other people to fuck.
It can't be that hard?