Bubbling : v. tr. (word coming from broth).
The verb "to bubble" has several meanings:
1. In the press, unsold newspapers or magazines are called.
A newspaper that boils at 10 percent means 10 percent of copies remain unsold.
2. Figurative meaning: Seething with rage: To be in turmoil, to be agitated.
to be overwhelmed with exasperation.
To boil from the coffee maker: to be cracked, crazy.
Ideas are bubbling and jostling in his head.