Lots of people game on the throne! (Heck, game designer Goichi Suda thinks up video games on the toilet.) Recently on Japanese television, Ninomiya admitted that he games for about 13 hours a day during his time off.
In the TV clip, the other members of Arashi went through Ninomiya's schedule, pointing out that his gaming was a bit overboard and nothing that he didn't seem to do much besides that.
Ninomiya was shown on the toilet, playing his 3DS. Hey, they're not portable for nothing!