A guide to finding toilets in Mong Kok has spread rapidly among mainland internet users since it was posted on social media website Weibo on at the weekend.
From Hong Kong with Love - the Complete Guide to Finding a Toilet in Hong Kong has been shared some 23,500 times and had generated almost 5,000 comments by last night.
It appears to have been written by a young Hong Kong man. The writer says he took half a day off work to walk around Mong Kok before writing the guidebook, which includes recommendations, maps, photos of toilets and jokes.
It comes in the wake of a furore over a mainland couple who chose to let their child urinate by the roadside during a trip to the city.
"As a Hong Kong citizen, I can choose to follow the mainstream and start shouting with my hands on my hips," says the author in the book's foreword. "But I hope I can make even the slightest contribution to healing the wound.
"I wish to end the hatred where it started," he writes, referring to the furore over the behaviour of mainland visitors to Hong Kong,
The book gives five stars - its highest rating - to toilets in McDonald's for their ease of location and use, but just three stars for cleanliness.
Bathrooms in both small and large shopping malls also receive praise for being clean, but lose marks for being more difficult to find, the book says.
Restrooms in hotels and government buildings are ranked third, followed by those in MTR stations and in commercial buildings.
If a parent finds that their child needs to relieve themselves urgently and they cannot find a toilet, the book recommends taking them to commercial buildings' back stairs, which are usually quiet and deserted. The writer suggests using diapers or plastic bags to clean up.
"We are fighting every day against an overloaded amount of tourists, a society where the rule of law is collapsing, crazy rents, mainland mothers coming to give birth here, a twisted economy and so on," the writer posted online.
"The photography [of the peeing toddler] is an outbreak of the accumulated anger in the society, but mainland friends only notice the result without knowing the process, so it's very reasonable that they don't understand us."
Responses from across the border have been positive. "A very lovely Hongkonger," one online comment read. "If all mainland and Hong Kong people can be like this, conflicts will be nothing!" read another.
Some other commenters, however, urged against pointing out where the city's bathrooms are.
"Don't all go there and make it even more crowded, ok?" wrote one.
The book also recommends a free smartphone application, Toilet Rush, which can locate toilets on a map of the city.