Have others show him! If it works, roll with it.
Vary your bait. I usually have something fuzzy up my sleeve, something squeaky in my pocket, and something delicious in my mouth. Bound to hit something somewhere.
Join a ring-handling class where they have gates set up. Work on a hard surface and toss bait ahead of you intermittently. Let him collect it at first, but after a while redirect so he's not stooping to sniff the floor when it really matters. When you enter the ring for real, pretend 'toss' bait to get his head up and catch his interest.
ETA: watch out in UKC, though... bait tossing is a big NO NO and you want to be very clear that you're just using a motion, not actually tossing anything.