LOL, my first time buying panties I went to the local Walmart at 6 AM when hardly anyone was in the store. I'd already figured out the size and style I wanted beforehand by looking around online. Once in the store I grabbed a basket and nonchalantly made my way into women's underwear section while no one else was around. After obtaining my sought after loot I went about the rest of the store and piled some other stuff over the top and then waited around until 7 AM when the self-checkout registers opened. Checked everything out at the register myself and no one ever noticed.
I laugh now at how paranoid I was being, but I guess it's a good way to do it if you are overly scared about being questioned for buying female underwear.