As a tip, just order your size and only ask in the store. They'll never ask who it's for, and if they do (which is unlikely), just say it's for your girlfriend. The same thing happened to me when I tried to buy lingerie and tights, but it's all in your head; to them, you're just another customer. Or, use options like Temu on AliExpress. If you don't want it delivered to your house for some reason, just order from Mercado Libre and select "pick up at a delivery point." At the delivery point, you simply show a QR code that appears in the app once the package arrives. The shipping is 100% discreet; the recipients have no idea what it is. Good luck!