This could be made into a fun and relatively stress-free game, which I might try with my dog.
Put one gutter down, shape the dog to go behind it, never over it or around it (which I have done already for drop on recall). Stay command, throw something forward (have a helper there to pick it up if the dog goes for it) and if the dog succeeds, throw something behind the dog. If the dog does not succeed, pick up the item, say too bad so sad, ask the dog to go back behind the gutter. Try again.
One thing that is important for creeping in obedience is to always have the dog go back for the reward, never forward. For example, with the drop on recall, the dog goes down and he is rewarded by a toy or treat or whatever thrown behind him. Always behind. Never in front. Dogs won't typically creep backwards. We also reward behind the dog for go outs (somewhat similar to a whistle sit).