Sam had walked into their bedroom, fully determined to talk Ruby out of tying him down out of the need for his own security, but by the time he had shut the door behind himself he found Ruby already latching onto him, mouth greeting his own gently, but strongly enough to urge on that maniacal hunger of his. Every kiss Ruby pressed to his lips was perfectly conducted, luring him straight over to the bed in such a way that Sam didn't even realize he had crossed the room and dropped onto their mattress until Ruby was swinging a leg over his waist and climbing on top of him. Thrown off, Sam shifted underneath her and reached to still one of her wrists, eyes snapping over to look at her throat as the repetitive thump-thumping grew louder and louder. It was terrifying, how much he wanted to take her blood right then. Sam Winchester loved his wife more than anything else in the world, but in that moment he couldn't imagine doing anything less than grabbing her knife and cutting her throat right open, so that the blood spilled freely from her body in such a way that he'd be able to have unlimited access to every last drop.
Sam licked his lips and looked up to her, frustration and desperation conflicting the stance he'd taken prior to entering their bedroom. She was going to argue with him if he told her that he didn't want to be tied down. She would refuse to feed him, she would up and leave, she wouldn't give him what he wanted. But then, if he did let her tie him down and she broke her promise out of the need to 'protect him', Sam wouldn't be getting any of the blood he craved anyway. It was a very complicated situation, because Sam wasn't so sure that he could trust Ruby right now. He didn't know where she really stood, as much as she was claiming to be all for spilling her own blood for the sake of his sanity.
But then, Ruby had always been so forward about his addiction before. If he got desperate like he was now, she usually up and left before they could get this far. She'd tell him to straighten himself out, to take a trip to the panic room - she'd say she'd steer clear until he got better again, because neither of them wanted to risk him losing control and doing something that he would very well regret later.
She wasn't doing or saying any of those things now. Ruby knew that Sam was aching for her in that unnatural way, she understood what being this close to her was doing to him. She wouldn't really play with his mind like this, would she? Ruby knew how serious all of this was. She wouldn't trick him. She'd either give him the blood or she wouldn't and, as of now, it looked very much like she was going for the former for the first time in a very long while.