According to Azalia Banks, Elon Musk suffered a 'botch penis implant' and honestly, it makes a lot of sense. 

The rumor flying around the internet is that Elon Musk had a penis surgery to implant a vibrating node into his Johnson. The only real source is an Azealia Banks tweet which Elon replied to with, “Accurate.” He’s a troll, but we’re really hoping that was a rare moment of honesty from the guy. 

He's probably only building sex robots to meet a girl he has something in common with.