Hey big guy. Let's go drinking at the beach, don't worry, I'm not going into the sea. I've eaten a lot and I can't sleep, ok? Are you sleeping? I miss you...
Remarks about the translation
the word giant could also be translated as monster, eager etc. I suppose it's used as a friendly vocative
"Hello Giant" would sound better as "Hey big guy (or girl)"
I think "big guy/girl" is the closest friendly vocative that we have in English. And "Hello" sounds a bit too formal for this context.
I'm not going to get into the sea -> I'm not going to go into the water
This is a more natural and common way of saying it.
Hey big boy(girl) or guy(gal)
Let's go have a drink on the beach, don't worry (calm down) I'm not going to go into the sea. (or I am not planning to get) I've eaten a lot and I can't sleep, ok? Are you sleeping? I miss you...