gistfile1.js

var f = function(){
  console.log(this.x);
};

var o1 = {
  x: 7,
  a: f
};

o1.a();

var o2 = {
  x: 666,
  // bind f to o1 even though it is attached to o2
  a: _.bind(f, o1)
};

o2.a();