If your vocabulary is limited to four-letter words during sex, you're missing out an opportunity to connect, and most importantly, take your sex to another level. Instead of listing one-word demands like "Faster" or "Harder," ask her what she likes. Don't be afraid to ask, "Does this feel good?"
Talk about what turns you on with words that aren't uttered in porn.
Some of the best sex comes via a real emotional experience. "You're beautiful" and "I love you" take on an entirely new meaning when said when there's no space between the two of you. It is ultimately the difference between mutual masturbation and bona fide lovemaking.