Otaki

From OMGWiki

Otaki is a blonde burly guy who wears spark plugs for earrings. He's almost never seen without Tamiya. He likes collecting good luck items and enjoys cosplay.

Early on in the manga he gets a girlfriend named Satoko, but after a few volumes she's never seen again.

Note: His name is also romanized as Ootaki, Ohtaki or Ōtaki.