He was so surprised when Guinevere threw herself at him and kissed him with such confidence, that at first, he just stood there. Then, instead of stepping away as he ought to do, he found himself kissing her back; he had certainly not forgotten how perfect that was, but the reminder was nice.
When she spoke, it brought him back to reality, and the need for discretion. She began to kiss him again, but he gently took her by the shoulders and moved her back a step, much as it hurt to do so. Glancing around to make sure they had not been observed, he said, "And I am happy to see you as myself, as well, but--" As he met her eyes, he sighed in disappointment. "We must not do that."