Toilet training help!

My ds1 was a breeze to toilet train. It took him about a month all up and he was night and day trained straight away. DS2 is proving more of a challenge however. A few days ago he completely refused to wear a nappy. No more nappies he said. Its a fight to get him to wear one to bed. Problem is he is yet to do a single wee or poo in the toilet. We haven't managed a single one. I have been sitting him on the toilet every hour, he sits there for a few minutes does nothing and then 5 minutes later pees in whatever room he's in. It's driving me slightly nutty. If we even had a single wee in the toilet I would see some progress and be prepared to ride it out. I don't know what I should be trying. I got lulled into a false sense of toilet training bliss with my first child.