sneezing in the sun

A friend was at my house on the weekend... he was lying on the couch and started to awkwardly crane his head back to the window..."what are you doing?" i asked, he didn't answer and had this weird face.. i thought he was having a fit. "Are you trying to look at the sun to sneeze? " " YEP - Waachooo!" he sneezed.
Why do people do that?? does it really work?? relying on the sun to get something out of you.. it's crazy!

I did some research:

Sneezing as the result of being exposed to a bright light—known as the photic sneeze reflex—is a genetic quirk that is still unexplained by science, even though it has intrigued some of history's greatest minds.

Aristotle mused about why one sneezes more after looking at the sun in The Book of Problems: "Why does the heat of the sun provoke sneezing?" He surmised that the heat of the sun on the nose was probably responsible.

Some 2 ,000 years later, in the early 17th century, English philosopher Francis Bacon neatly refuted that idea by stepping into the sun with his eyes closed—the heat was still there, but the sneeze was not (a compact demonstration of the fledgling scientific method). Bacon's best guess was that the sun's light made the eyes water, and then that moisture ("braine humour," literally) seeped into and irritated the nose.

Basically they can't work it out --- same with rolling your tongue. Ah the human body... what a mystery.