The actions and emotions a person shows when they are on the toilet and trying to shit something big...and it hurts. Similar to the emotions and actions while preparing for a roller coaster dive with the rejoicing hand raise at the end (woohoo!).
I didn't shit for days but when I did it was a roller coastershit!
Boys who enjoy yaoi (a genre in Japan that contains sexual and/or romantic relations between two men); literally translates to "rotten boy"; corresponding female : fujoshi