I have tried a LOT of toys, a LOT of treats, a LOT of be dragging bait bags on the ground to get the prey drive going, and no tug ever. The closest I ever came was getting her to pounce on a bait bag (but not mouth it) and maybe clamp on a toy (but immediately release it). I *know* my dog can tug b/c she tugs with other dogs!! So her breeder told me something to try that NO sane dog would ever NOT tug....a raw chicken thigh in a sock. It took a few minutes to get a real tug, as anytime I tugged back she would immediately "give up" to me. Eventually I got a nice full bite on the sock, butt on the ground, throwing her weight backwards tug. Unfortunately the game was ended sooner than I planned because the sock died. Next SchH practice I will be there with a pack of tube socks and a pound of chicken!