This is an advertisement for some sort of hair styling product. It's drawn by Inoue Takehiko, who I posted a blog on about not too long ago. I saw this ad from a Japanese TV show called Ametalk, which is basically a variety talk show where they have some sort of theme and get certain comedians to talk about it. They have themes all the way from, 'Shy comedians', 'High school loser comedians'. Once in a while they also talk about their favourite animes; some animes that have been past themes are 'Gundam' ,'Neon genesis Evangelion', 'Grappler Baki' and others. One such episode had a Slam Dunk themed session, and they showed this advertisement to try and show the greatness of Slam Dunk.