"C'mon Cas! Breathe some in. It'll just feel like cold air." Dean all but whined, squishing the blue balloon in his hands. He'd been trying to persuade Castiel to inhale helium for about an hour.
"No Dean. I am aware of the reaction my body will have to it." Cas repeated, sounding vaguely annoyed. Dean groaned a bit and tried not to think about Castiel 's body having reactions because he was on a mission. A mission of mischief.
"Don't be a spoil sport, Cas! C'mon! Sam isn't even here." Dean prodded the Angel's leg, which was thrown haphazardly over his lap. Castiel HAD been educating himself about the internet before Dean had gotten up the urge to pester his poor Angel.
"Dean I am not a toy. " Cas muttered, returning to scrolling down the web page.
"Caaaaaaas. C'moooon! Just once!I'm beggin ya! It'll be great!" Surprisingly, Dean was not above begging. Castiel paused his internet endeavor and spared the hunter a wary glance.
"Perhaps… it does mandate an experiment to see if it will affect me now that this body is my own…." Cas spoke slowly, with a thoughtful expression on his tilted head.
"That's the spirit!" Dean clapped him on the shoulder and handed over the balloon. Cas held it in consideration for a short while and then raised it to his mouth. He bit a hole in the tip and inhaled the entire balloon. Dean's face lit up and his eyes crinkled and he waited.
"How do I know if it affected me." Cas's voice was higher pitched, but not Alvin-y. Dean still lost it. He roared with laughter as Cas's face twisted up in an unhealthy mix of horror and fascination. But it wore off while he was thinking about it and they were left helium-less.
"That was…. Interesting."