I like the figurative meaning of this phrase, as it makes me think the person has shrunk and now fits in your pocket.

We use it when we do something that makes other people like you or do what you ask from them:

• Con ese gol, “el cóndor” Rueda se puso a los hinchas en el bolsillo.
• Cuando dijo que somos el mejor público del mundo, se puso a los argentinos en el bolsillo.
• Se puso a mis viejos en el bolsillo

You might also want to read these articles:

• Expressions with MIERDA
  As a sequel to our previous post, today we focus on MIERDA and its multitude of meanings.
• The body and bodily functions
  A handy list of things we all do but rarely (care to) learn in a foreign language.
• Spanish Class | SNL
  A fun sketch from Saturday Night Live where students are in class ‘learning’ Spanish.
• How to go about with reading in Spanish
  In this post I want to make you want to read, even if you feel you’re not ready for it.
• Implied subject
  This post deals with a little tweak that can make your Spanish sound more natural —dropping the subject pronoun.
• Start Shadowing now!
  Today I’ll get you started with shadowing, so your Spanish speaking skills go through the roof.