The trick I use in moments like this is to find a stick (about two foot long is good enough thin and flexible) and a nice semi firm dog turd. Take stick and apply dog turdular mixture by using a stirring motion.
Apply mixture to offending persons door handle, gates,car door handles etc. Sit back and watch the fun.
There's nothing more satisfying as watching a person sniff there hand and then seeing the realisation set in "I'm covered in dog egg!"