Well, first, the obvious:
You can't
breathe a
person. I mean, you could give it
your best shot, but it just is not going to
happen.
Second:
It's usually used in a really cheesy
manner, that is, it's become so over-used, that it really doesn't hold much
significance at all.
Actions generally speak louder than words, but if you're hard-up for a way to
express your feelings, avoid this supposedly "
romantic" phrase, and use something
infinitely more
appealing, such as:
"Um, you have a nice
eyeball, oh, if you would only let me
lick your pupil, suckle your
eyelids, I would be the happiest human
alive!"