If he wasn't already sure about this, that sound she just made would have tipped him over the edge completely. When he heard it it was as if it triggered something in him, a desperate need to do whatever it took to illicit another just like it. The sudden need was reflected in the way he returned her kiss, with urgency and fervour that hadn't been present when their lips met previously. Slowly, he urged her to move backwards, never breaking the kiss with her as he did, until she made contact with the sofa.
They both lost their footing then slightly, thanks to the momentum that accompanied colliding with the sofa. Luckily the landing was soft thanks to the aforementioned sofa and Sam was able to gain enough control of his own stumble that, although he did technically land on top of her, his weight wouldn't crush her. "You alright?" He asked her, finally having to break the kiss and resting his forehead against hers.