When you are riding your bicycle and suddenly you see a puddle in front of you, you squeeze the brake. Here, when you squeeze the brake, a set of two pads near the wheel hit the wheels, causing friction and stopping the bicycle.
When you are playing on a slide, it may be so quick, that when you get to its end, you might get blown off the end. Therefore, to avoid this, we put our feet on the slide, and friction is generated, stopping us at the end. Sometimes, if we do this, we may be wherever we did this.