Goddayum 

Interesting and amusing way to say 'Goddamn,' brought about by some random flash video and utilized constantly by Hirosuke.

And, occasionally myself.

Goddayum by Leiko October 3, 2004

GOD DAYUM! 

Harrison's favorite expression when he's surprised or pissed. Or both. It depends on his mood.

Brian:hey Harrison i just got laid...

Harrison GOD DAYUM!

GOD DAYUM! by harrison ambrosio January 12, 2009