Why are you desperate in the first place is the real question.
just let him know...geez, if a woman ever showed her feeling for me first I would be so so thankful
Just ask him out. Either way you move forward.
Drop subtle hints, if he takes the bait, move on to the next phase.
Just be yourself and act normal around him.
By letting him know you would like to take a drink, but you are not dying of thirst. Never let a man know you are thirsty. That gives him the advantage.
Ask him out.
You don't. He has to show his feelings first, otherwise you will appear desperate.
when you see him, reach down, unzip his zipper, pull it out and lick it
Never let on that you're desperate, but very self confident and interested in him...
Just keep talking to him....eventually you'll know what to say...it'll come naturally!