Jack grins, wide and wicked despite the fact he's panting for breath and bucking helplessly into Spike's hand as he pumps him, good and steady.
"Always."
He's not expecting any vamping out. Spike's made himself clear on that front and, disappointing as it may be, he'll respect that. (Even if it won't stop him fantasising about it, which means, okay, this being a dream, it could happen, to his mind.) Either way, he's not even thinking about fangs and blood-drinking - at least, not until Spike goes for his neck. He's got layers, yes - two collars and a t-shirt to get in the way - but his shirt's open at the neck and there's skin to be had, especially the way he's got his head thrown back as he gasps for air. Air that's abruptly even harder to come by when he gets blunt teeth nipping at sensitive skin, something that's always a turn-on for him even when the teeth don't belong to a vampire whose damn near had him coming in his pants from biting him in the past.
All thoughts of turning the tables, of losing clothes, of getting Spikes trousers open - hell, all thoughts, period - fly out of the window. All he can do is grab at Spike's head to try and keep him there as he tips his head back as far as he can to give him better access.