Favorite type of panties? Lace bikinis. But during the summer I tend to stick to cotton bikinis as I found out in my teens that if I sweat a lot and am wearing anything else that I'm prone to yeast infections. Cotton definitely helps move moisture away from your body! I like these really silky cotton bikinis that I can only find at Dillard's. (Can't remember the brand.) I wear thongs sometimes, depends on the clothing. Commando if the outfit calls for it.
Do you have period panties? I do, those would be the all out comfortable cotton bikini Fruit of the Loom/Hanes/whatever kind I can buy cheap at Walmart and replace as necessary type.
Do you wear special panties on your o date? Not yet, I can't figure it out ahead of time yet. LOL But I do have those special matching sets that I wear when I'm feeling friskier than normal!