The title tells you exactly what's in the book. You'll find lots of smug ads, vaguely familiar or pointlessly famous personalities, all with lots of penises drawn on them, plus some crude comments, some mustaches, some other naughty bits too.
But why does such crass stuff hold your attention? I think the mesmerizing element is that you understand why someone wants to take the juice out of big media by applying some nasty juice (at least in drawn form) of your own. Also it's a slap-stick level snort-laugh, the same sort of dumb thing over and over, but even the repetition has a strange humor (and insight) to it.