"Sexy Jackass" I love that!
I do this quite frequently, as does my brother and middle daughter. I try not to do it around people I don't know well, but occasionally will in public. I'll shout out random words, nonsense words, or bits from commercials, sometimes curse words. I also call people odd names for no reason.
I laughed so hard yesterday after this exchange with my five-year-old boy:
Me: Brandon, you're a Lipitor. (Lipitor is a pharmaceutical)
Brandon: [laughing] Oh, yeah? Well, you're a Requip! (another pharmaceutical)
So, of course, now I go around saying "Requip" all day long.