I've heard people use the phrase "I'm not drunk..." a lot. Usually it's "I'm not drunk, I can totally have another drink." or "I'm not drunk, I can totally drive." (no, you can't). But, I don't think I've ever heard this one before.
"Why did you fail your field sobriety test, ma'am?" "I'm not drunk, I just have big boobs!"
Yup, a lady down in Port St. Lucie, Florida tried to use her large chest as her reason for not being able to properly balance on one foot, walk a straight line, and touch her fingertips to her nose.