Press the bulge.
Apparently these little rubber underwears from Bandai are all the rage for smartphone owners in Japan because Japan is Japan and I'm tired of trying to understand. They come in a variety of styles and are sold randomly in plastic capsule machines for 200 yen ($2). Didn't get the pair you want? Try again! Still didn't? Now would be a good time to reevaluate just how important having a particular pair of rubber underwear for your smartphone is to you.
Keep going for a shot of a dispenser a bunch of the different styles, and some wack-ass commercial.
Thanks to Alleycat, who needs to stop meowing outside my window at night when I'm trying to go to sleep.