The Bamboo forest is a location that appears in the Touhou series of games that the Yukkuri meme started from. You can find more information about it at the Touhou wikia. Although described as a dangerous place for humans to go, in Yukkuri stories, it's almost never the case. Although few, most stories taking place in the bamboo forest involve a group of people capturing a Yukkuri from the forest, and returning home to have fun with it. For example, in one instance Mokou captures a Yukkuri Mokou, and then proceeds to impale it with bamboo sticks, cover it in oil and set it on fire, and finally pulling out its insides through its eye sockets, cutting off the top and removing its filling, and other things.