Kanye West ' s fully embracing the mentor role for his daughter North West 's rap career ... bringing her out at his Mexico show to perform her new song. The music legend performed in Mexico City Friday night -- his first show in the country in nearly 20 years -- and, North joined him onstage to play "Piercing On My Hand" ... a song which references the dermal implants she got in her right hand a few months ago. Check out the clip ... like father, like daughter when it comes to the outfit --