Sentence:  This year's installment of Theatertreffen Berlin, the spring festival of the best of German-language theater that has been going strong since 1964, required some <WSD>sitzfleisch</WSD> — that is, the ability to stay planted on your derrière without fidgeting for the duration of a Wagner opera. 
Meaning of the word marked with <WSD> tags:  The ability to endure or carry on with an activity.