This is a form of art typically performed by drunks once enough of their kebab has been eaten. The leftovers are either: thrown on the floor, posted through mail boxes, or smeared over shop windows.
Just as Ian said: 'I've had enough of this rancid shit', he threw the kebab over his shoulder. It landed with a pleasing splatter and decorated the pavement with a wonderful array of patterns, colours and textures.
Meanwhile, Simon was trying to make slithers of donner meat stick to shop windows.
A couple of swampbeast bitches walked past and said 'wow, a pair of kebab decorator'!