It would be appropriate if their first time together didn't involve anything more than this. It's always been all passion and no form, all rutting and grinding without any sort of thought behind it. It's not like he can think all that much right now anyway, with the heat that is Jack pressing down on top of him, all breath and pulse and life. That, more than anything, is the most expected turn on with being with the living. They're frail but damn if they're not addictive.
He groans against Jack's mouth, rolling his hips up to meet him with fierceness and although he's not sure he can come like this (vampire stamina can be a bitch) he'll damn well give it a good try. This being a dream it's not like they have to think about refractory periods or, he guesses, lubrication.