I just ordered a nylon bone for my dog that has little perforations in it. The bone itself is supposed to taste like peanut butter, but you can scrape peanut butter or cream cheese over it, and the food fills the little perforations, affording the dog quite a bit of licking time. I think it came from Pet Qwerks.
Flavorit BarkBone Peanut Butter Flavor Infused - Dog Chew Toys