Felicity was so overwhelmed by his kindness and easy going nature that there was nothing tentive about how she kissed him in return. She was glad that he'd made the first move, but once given the go ahead, she took what she wanted. One arm was still propping her up and thus unable to really do anything, but the other spread across his cheek to give her the leverage for a really deep kiss.
She threw one leg over his, ready to go in for the kill ... so to speak ... once he gave the go ahead. Arousal was already there, there would be no fumbling with clothes. This was easy.