John may not be far off in his 'timber dream' interpretation, according to http://www.sleeps.com/analysis.html at least. Or it could mean nothing at all http://mentalhelp.net/psyhelp/chap15/chap15t.htm unless he has that dream (or a variation of it) again.

Another plausible explanation is that Stephen remembers his bonfire experience so fondly that he wants to prepare another one from his waste (perhaps a metaphor for 'wasted time'). He might even enjoy another bonfire without the neon vomit.

Either way, this scatalogical excursion is neither unexpected nor unwelcome. I can't count the number of times I was told that I was full of $#it during my formative years. I also know that I'm not the only one who heard that!

Maybe Mastandreas do camp, or at least enjoy burning quantities of wood (which, in the light of Stephen's dream, might give new meaning to 'shooting the $#it')