Not gonna pretend I have answers to all those questions but I'm betting that beach is Kamine Island which they were transported to in the beginning of season 2
Not gonna lie I used that trick as a teenager, if you haven't drank much before it's really no wonder you're struggling with it, I think everyone does the first few times.
I always drink liquor straight, mixed drinks have a lot of extra liquid that can make people more prone to vomiting, I always drink it straight and chase it seperately with a coke or something.