Is underwear color and it's significance Japan only or is it more a global idea?
Broadly speaking, it's global. Victoria's Secret wouldn't exist if people didn't care what their underwear looked like, especially their "game underwear" for "game day".
Beige underwear is meant to be nondescript, so that even if someone catches a glance, they might not notice the difference between thigh and underwear. Also, beige hides any embarrassing stains better than white will. That said, it's also boring and ugly and definitely not what sends the impression that you're sexy the way that, say, black lacy Victoria's Secret underwear will.
To...The same Hirotaka who's famous for being hard to determine when he's awake and when he's sleeping with his eyes open!Dear, dearClass is over.That Hirotaka was also a guy.I know more than anyone...That he wouldn't call me to his house and do something, or even have the gutsNarumi remembered.And also that her underwear was beige...Calm down me!! What am I so nervous about! This is Hirotaka we're talking about!