Bollix, as heard on Dempsey's Den on RTÉ, is a colloquial term for testicles, used, as far as i know in Ireland and the UK primarily. This could extnd to Australia and other commonwealth/ex-commonwealth countries. It can be spellt as Bollocks, which I would consider correct or as Bollox. The term is regarded as a vulgar or slang word and should be used only for such reasons, or where it would be deemed acceptable for humourous conversation.