If your g/f feels as though talking sounds corny, put your mouth to better use and kiss something or suck on something while you are having sex. My g/f in college loved it when I licked her ears and her tits when we did it. She said that talking "ruined the mood". Of course, this meant that 1) I said nothing, or 2) we used positions where my aforementioned suggestion could be possible. Fortunately for us, she LOVED missionary.

my 2 cents...good luck!

rabbit