The victim was walking her dog, a terrier, when a man approached and then exposed himself. Then the terrier growled and bit the flasher on his arm. Sgt. Ian Dowling, from North Cotswold police said
, "the dog seemed to have acted instinctively and was not urged by the victim to attack".
The incident happened at 1930BST
on Thursday and police are looking for a man who has large, bluey-brown eyes and was wearing navy blue tracksuit bottoms, a light blue top and a black hat. He is also described as slim and around 5ft 2in.
Police have asked local hospitals if they have treated anybody with a dog bite on his right arm and are appealing to anyone who knows somebody who has an injured arm to contact them.