Since I'd already done some value building for the fake calming cap (infant onesie leg), I slipped this one on West and started feeding him. He pawed at it a bit, but the nice thing about this (vs the fake one) is that it stays on even when he paws a bit, so I let it extinguish. What he hasn't figured out is that he can open his mouth with it on, even if he's not actively eating a treat, so he's lying at my feet panting a very wet gurgly pant with his mouth shut! silly boy. He's actually accepted it quite well. He walks around a bit with it on, and I toss him kibble now and then. Sweet!