Physically, the only thing that would need any kind of prep is a tail buttplug, and you'd want to be clean for that, lol. For Pup hoods you'd want to take off any jewelry that would get in the way. Get contact lens or glasses that you feel comfortable fitting around the hood, or through the eye holes. If you plan to do any pup mosh, try to avoid wearing anything pointy so you don't poke others or their gear. This can include anything with a buckle (like cuffs) that have pointy parts in the buckle. Thats the main advice i can think of for pup play specific gear.