"Ass top driller" (Perhaps NSFW? Comedic partial ass exposure)

Water Cooler
#1

http://www.cracked.com/blog/5-amazing-japanese-tv-shows-that-prove-our-species-doomed/

Is this a normal pastime in Japan?

#2

NSFW warning would be nice about Gif

#3

I did not initially think it’s NSFW, but comment is noted.