nothing! its brandy you douche
1) find a nice crystal cup/glass (or a small jar or other non-plastic vessle)
2)find some ice (preferably of the cubed variety)
3)place ice INSIDE said vessle
4)pour brandy over top of the ice (which is still inside your cup)
5) wait a second (or more, so it can you know get "cold")
6)dont slam it, don't let it sit there and get all watery either, just drink it