A play on words with Europeans and peeing - if you don't get it say it out loud.
The Europeans are Euro-peeing their pants about the newest episode of Doctor Who on tumblr; it must be good!
American Friend - I can't wait to go on this new roller coaster!
European Friend - I'm not so sure; it looks scary.
American Friend - Oh, quit Euro-peeing yourself and let's just get on line already.
European Friend - Ok.