Go on, you little slacker! Go on, you idle, worthless little boy! The whole trouble with you is that you're bone and horn idle. You eat too much, that's why.
'Bone idle' I know, but I've never come across 'bone and horn idle' before. Googling it brings up only three results, one of which is 'Such, Such Were the Joys'!
However one of the other Google results suggests that 'bone and horn' (usually shortened to 'bone') is rhyming slang for 'born'.
That's plausible, but I have one reservation: 'bone' and 'born' are only one vowel sound apart (at least in my non-rhotic accent), so using one to stand in for the other seems a little... pointless.
In all the other examples of rhyming slang that I've come across, the original word and the replacement word are not at all similar-sounding. It must make for a more effective cryptolect, if nothing else.
What do you think?