Dewey suggests Del show his love through nostril flaring. According to this scholarly article on the scientific research site "links2love.com" nostril flare is an obvious sign that, according to these researchers, "he's way into you." Or he has severe allergies. Who knows.
But if you think about it, this makes perfect sense. What is the time of year when relationships are most likely to blossom? Without Googling it, I'll say springtime. Which is also allergy season, or when nasal flare-up is most likely to occur. The point? If you fell in love with your significant other in the spring, you may have fallen for each other not through subconscious body language, but thanks to pollen buildup.