Police say at flasher exposed himself to a woman in Newton-le-Willows.
The incident happened last Wednesday at around 8.45pm.
Officers say a man in a white saloon car approached a 52-year-old woman, who was walking along Park Road North, and attempted to strike up a conversation.
He then exposed himself before driving off.
Police say the man - who was white and in his 20s - was wearing a t-shirt but no trousers.
A police spokeswoman said: “We’re appealing for witnesses after a man indecently exposed himself to a 52-year-old woman whilst she was walking along Park Road North in Newton-le-Willows.
“Luckily the woman was able to call the police and was physically unharmed from the incident.
“Anyone with information or who may have seen a car or was also approached by a man that matches the description at a similar time in the surrounding area, is advised to contact us via @MerPolCC or by calling us on 101 quoting crime ref: 18200070199”.