Hi, I got advice from RU recently, and Barley Straw, was recommended.. I've got some and have started to use it.
But I always flatten it down like a bed layer, I too am a bit paranoid about them having a mini panic and running into a strand... I may seem silly, but I try to make up 'the beds' with the Buns there, and try not to change the angle of their ' quick run ' zones.. I pat it down, nice and neat, and then they have control.