Taking the offered glass, Finn was not about to say no to the man nor to a sugary drink. You couldn't go wrong with sugar drinks.
The sharper look made Finn look away. "I was taken by the First Order as a child and brought up as a Stormtrooper," he started cautiously as if that right there would make the man hate him. Finn did not expect pity- he didn't need pity- but because he, himself, hated what they had been trained for and done Finn thought any legendary rebels would hate him too.
"Uh-" He swallowed, holding the glass between his hands on the table. "When I went to escape I grabbed Poe to pilot my escape, found Rey on the planet we had been attacking, and..." Finn left a lot unsaid for the sake of making his introduction short. "Rey knew I was a force-sensitive somehow, but I never really thought about it. About how I did not need to see a target to know it was there... how I found Rey to begin with..." Finn shrugged, finally lifting the glass to drink the sugar liquid.
After the first sip, he stared at it in surprise and drank some more. "I've never had anything like that." He mentioned, offhandedly.