This is very easy to do, but the awkward controls make it a bit challenging.
To make this easier, concentrate on only two buttons (one from each team). Have one of you cars drive to your goal to become the goalie (you have to drive into one of the glove icons). Now, if you simply stop playing that button, the car will just tend the goal for a second and then drive off. The trick is to keep tapping the button. Each tap will cause the goalie to change directions. By continuously tapping, your car will stay a goalie as long as you don't touch one of the sides.
Now, while using the other button, have an opposing car bump the ball into the goalie. This is still a bit tricky as it takes a little while to get accustomed to the controls.
After figuring out this method, it took me about two minutes to get the achievement.