When a man during a young relationship really wants sex, but the girl does not. However, the girl wants to make the guy happy and let's it happen anyway, not enjoying it that much herself.
I really liked him, so we had some forced pity sex so we wouldn't dump me for a whore.
Short-hand for the word floccinaucinihilipilification, meaning the estimation of something as valueless (encountered mainly as an example of one of the longest words in the English language).