PLEASE HELP
DS (6, nearly 7) is so farking untidy. He gets some sort of story going on in his head, he goes and find whatever he needs to make it a bit more real, and then when his brain moves on to the next inner story, he leaves whatever-it-was wherever he is. Multiply this by ten times an hour.
We usually have a tidy up before bed, put everything in a basket at take it upstairs. The trouble is that he needs prompting every night and has never, ever altered his behaviour to take into account the fact that he's going to have to tidy up. It's like it's a surprise to him, every singly farking time.
The last thing I want to do is to charge round after him prompting him at every turn to put things away - I don't mind doing it later in the day, he's a kid, he needs to play, etc. But atm I clear the kitchen table, I turn round, and he's put some football cards and a bit of lego technics down and scarpered 
I'm so very not an obsessively tidy person but I don't think I can take many more years of this. Are there any heavy-duty behavioural change techniques I can use that aren't just nasty and boring?