Here's my plan:
Put lube, courgettes and wipes on counter (would love the vodka but am off the booze)
Very good.
Bat eyelashes
Great. Remember to pile on the mascara and add false lashes if you need to.
Say 'I read an awesome article in The Lad's Bible today...'
Uh-huh. Good.
Randomly touch his arm (both ewwww and tricky because he will be behind a counter)
You could sort of "trip" on your way to counter and kind of let something (the lube?) kind of go off the counter onto his side (almost into his lap) and lean over to "catch" it, making sure he cops an eyeful of your unbuttoned top/Wonderbra? That way you were "only" trying to stop your shopping falling into his crotch, not after a grope.
Do eyelash thing again
Yep. Can't do enough of that. Well, not so much that he thinks there is a bit of grit in there! Unless you want to try the "I've got something in my eye routine", but I think that's just a bit advanced for you right now.
Leave shop with a strut/swagger/wiggle, while he thinks 'She must be a friend of my mum's'
That's the stuff. He will think you're a MILF. Why not?