A skateboard trick where you grind with your back truck and hang your front truck over the rail/ledge.
Your board can touch the rail too, just make sure and dip your front truck as far down as possible. Fs Feebles look very similar to bs smith and bs feebles look very similar to fs smith. The main difference is how you approach and where your weight is when doing the trick.
Can be done on ledges. But it's recommended that you only try that when you can lock your back truck in and turn the board to make it look good.
The first grind Johnny learned on the rail was a bs feeble. He was scared to do a 50-50 so he did the closest trick to a boardslide he could think of.