Slap some cooking oil on that sucker, no one will think anything if you are buying something. Hell, even some non-buttery Crisco could work just fine. But lubes are plentiful in selection in even the smallest grocery stores these days for a reason. There was a time you could only buy KY jelly. Now you can buy a dozen different brands and slickness where you buy milk.
Chances are the people who are at the store also buy the stuff too.