I've seen the Lonely Urotsuki with the Stretch effect three times and I haven't gotten it either...I tried crying in different spots, even crying in a bunch of different worlds and got nothing. I deleted the info for it because it wasn't really the 'sure' way of getting it.
Also, what's the deal with #97? I've interacted with everything in the wallpaper as well as talking to the specific TV guy at the Underwater Amusement Park like the person below said, and I did that twice. I'm thinking that maybe these wallpapers are like a random event, like maybe every time you go to sleep you have a 1 in something chance of getting the wallpaper after fulfilling the requirement?