The punch connects, turning him around from the force of it but he catches his footing soon enough, yellow eyes locking at Jack's in a toothy grin.
"That's the point, Jack!"
Of wounding, perhaps even fatally if that's what Jack's going for. He won't bite him outside of this dream but here? Who cares? It won't harm anyone and considering that Jack nearly came in his trousers that one fateful night, Spike has a feeling he'd rather enjoy it. Regardless he lunges, all teeth and bloodlust, aiming a return punch to that smug face.