For all intents and purposes -- and setting aside any and all Twilight references -- let's assume that Bast was a drug. Sure, let's say he was heroine. Why not? The point is that just one hit isn't quite enough. Penny's lips burned after the kiss, and her heart did a double beat in her chest. If she had no restraint at all, she would have ignored his virtually meaningless question and gone in for another kiss. She would have draped her leg around him and straddled him, kissed him until he was blue in the face. That was what she wanted to do.
But Penny, whose brain had now decided that its primary function was indeed thinking, knew better than to do something like that. She knew that she was a rookie, and that rookies made mistakes, careless ones at that. And no, she was not about to take any chances or make any mistakes, not with this one, not now or ever. Luckily, Penny had quite a bit of experience with withholding things from her that she wanted, so though it was difficult to resist the urge to feel his lips on her and all over her, she managed it all right. She couldn't help the way she bit her lip though and just stared at him with big and innocent yet longing eyes.