With no hesitation apparent, the King of Hell dipped two fingers into the concoction of the various herbs (all of which included an angel's feather, tears of a dragon and a pinch of the sands of time) along with Anthony's blood and began to smudge it onto a back door in an extremely particular pattern. It looked very much like Satanism to Anthony, but then again, they were both demons (the same demon, actually), so such things were a way of life to them. Once Crowley had finished his masterpiece, he stepped back from the door a few paces, tilted his head at various angles in order to check if it was a hundred per cent accurate, then gestured for Anthony to take his place in front of the door. When the younger demon (naturally) declined, yet again reluctant to step forward, Crowley exhaled, clearly trying to keep as patient as possible (or rather, non-patient, since patience wasn't one of the King's… non-virtues), then proceeded to place an unforgiving arm around his shoulders and forcefully walk him forwards. When Crowley saw Anthony staring confusedly at him with a specific air of annoyance, the King of Hell rolled his eyes and began to explain.
"I'm guessing you're going to throw another hissy fit at me if I don't tell you what's going on, which won't exactly help my blood pressure – or, your blood pressure. Now, I don't know how much you know about blood spells, but, anyway, this is one of them which will enable you to get back to your own time, hopefully in the right place too. It won't take a minute, but when I finish reciting a certain Enochian invocation, all you have to do is open the door and step through. Got it?" His tone was vaguely patronising, and tainted with sarcasm, but Anthony was almost used to it by now, since he realised that Crowley likely spoke to everyone like that. Anthony nodded in response, and gestured for him to go on with the spell.
"Kah-nee-lah puh-goh, kah-nee-lah puh goh…" Although Crowley's voice sounded very much the same, it had an eerie monotonous sense to it as he chanted through the adequate speech required for the blood spell to work sufficiently. As he approached the end of his speech, the sigil drawn on the door began to glow a fiery orange, its intensity near-blinding Anthony, which forced him to avert his gaze temporarily. The King of Hell was not so weak-willed, however; instead, he embraced the fire and stared deep into the heart of it, making his own eyes appear to burn with a profound obstinateness. Once Crowley realised that Anthony hadn't yet obeyed his specific instructions, he turned to him fiercely.
"NOW! You have to go now, or else you can't get back, you moron!" He yelled ferociously, glaring at Anthony as if he were stupid. Evidently Crowley though so. The King reached out a hand to haul open the door, and began attempting to shove his younger self through it, but Anthony rebelled.
"WAIT!" Unusually, Crowley actually listened to him, but still remained clutching onto his the sleeve of his suit jacket. Anthony continued, still in disbelief about the fact that the King of Hell was paying any attention to him. "I have to know – do you remember me at all? Do you remember what you were like, what you did in your past life? The time we spent with Aziraphale, our angel, in the Ritz? That I did try to be evil, but inevitably I was a good person, deep down?"
"Shut up, you bloody idiot!"
"NO! Answer me, just this once!"
Crowley appeared to be genuinely considering Anthony's words for a moment, delving deep down into his distant memory for a glimpse of the things his younger self had mentioned, but nothing significant came to mind. "I remember many angels, but only ones I have tortured. There's no good in me! We're demons, you and I – to the last drop! Redemption is impossible for creatures like us. You might as well embrace the evil and use it as an advantage, before someone seizes your vulnerabilities and uses it against you. It's the best way. I don't know what you did in your time, if abiding by my advice would keep you like yourself, or like me. Perhaps you have no choice, in the long run. But whatever you do, just maintain your free will. Don't let any other nescient demons of higher authority drag you down with them. That was the key to my own success. Now go!"