I stumbled on this old movie, spectacularly called Uncovered.
I didn't think much of the movie itself, it's quite unremarkable, though the lead actress is very cute.
But...every time she has an intimate relationship, or just gets close to someone, she sneezes. And they don't sound fake (which makes me wonder about how the actress does it!)
There's actually two moments when she sneezes uncovered *into* the guy's face, and I couldn't help thinking of everybody here who would die of enjoyment watching this LOL
Also laughed a lot, wondering if the title had a double meaning. Maybe the director was one of us, what do you think?!!! 
It can easily be found in streaming on putlocker's website. I don't know if I can post the link directly, but it's easy to find. If you guys need the precise timings of the sneezes, I can probably find them again for you, so PM me.
Cheers!
E.