a taser? kidding! Dogs usually sniff around an area before letting loose. Observing this, my mother tried sprinkling cayan pepper around her flower beds. Dogs AND cats seemed to avoid them like the plague from then on. I don't know that it works every time, but it's worth a shot

A dog smells where another dog has peed before.. to mark territory.. so you might want to do some gardening and put fertilizer, etc. to throw off the scent .. vicks inhaler works wonders .. also works for humping dogs.