I just kick their cart and say "Yeah fucker I have tampons AND PADS cuz im a heavy bleeder...and?????"
Just kidding I dont, but I will literally stop my cart and stare at them until they see me and Ill ask, "Are you done now so I can finish shopping? I stopped so you could get a good thorough look into all my bizness. Im gonna go buy condoms (insert roid creme, enema, vagasil, etc) now-wanna go with me? Ill let you pick the brand."
They usually dont let me finish the sentence before they walk off embarrassed.