SO FINE was cheeks, not crack. (*sigh* why do I know that off the top of my head???)
I never saw the movie, but was forced to look into it about 25 years ago when my new brother-in-law, the stockbroker, recommended it. I do have a lingering image, now that you mention it, of Ryan O'Neal's cheeks showing at the rear of his trousers (jeans?) and the butt itself covered by clear flexible plastic. Perhaps that was on the cover of the videotape.Always an ardent supporter of American enterprise, my b-in-law liked it I think because the plot had to do with the entrepreneurial spirit and marketing. Yes, that IS a good question, why DO you know that off the top of your head?