Instead of taking stuff away from a grave (grave robbing) you are adding to the grave site.
Usually taking the form of
revenge; by having lunch sat on their grave, tossing all the empty beer cans, wrappers, and crumbs over it. Then lighting up a few smokes flicking the
ash about and grinding the
butt into the headstone.
To finish you can then urinate and/or take a dump on the grave, using the flowers or cards to wipe with.
Steve 'Hey
dude do you feel bad you
will never get your revenge on Mike for bullying you?'.
John 'Naw I spent my lunch grave slobbing his plot , so it's all good now'.