lyric stump

When you are producing words for a song (or something like that) and you all of a sudden lack any quality in your lyrics or genuinely can't think of any, this is called a lyric stump and it is a very common problem among all types of musicians, and some solutions involve:
Listening to Music
Reading something
Painting or looking at other paintings
You get the idea.

This will often happen if you are changing how you are singing about something and/or what you are singing about.