Any natural ways to increase sperm motility?  assume we don't smoke, drink, no exposure environmental toxins or tight fitting. Have good diet already.

That Hits Most. Well, you have excluded the most common methods. The only thing i might add is timing. Sex too often depletes the sperm and can force immature sperm into battle. Too long between sessions can also affect sperm. I would suggest no more often than once a day, but at least once a week. You may also want to have your sperm evaluated to see if there is a motility issue.
Sperm Motility. Sperm are happier with cooler temperatures (boxers are better than briefs and avoiding hot tubs/hot baths is helpful). Also if you are trying to get pregnant, skipping days between intercourse allows the man's sperm count to recover.