Growing a Mushroom
getting an erection, usually used when a surprise boner begins to form
As Jim's pants started to get tight he stated, "damn i'm growing a mushroom".
Growing mushrooms
Used mostly in anime and manga, the term growing mushrooms refers to when a character has become immensely depressed or saddened. The character is often shown to literally grow mushrooms on their body, signifying that their soul is, for the time being, in a dark and dank place. (Mostly occurs with more dramatic and over the top characters who can't stop crying every 2 seconds 😒)
Senpai: (crying because the girl of his dreams thinks he's dramatic and egocentric)
Girl: "Senpai, quit growing mushrooms around me; the smell is absolutely noxious!"
Girl: "Senpai, quit growing mushrooms around me; the smell is absolutely noxious!"
growing mushrooms
Sitting for a long while
My little brother hasn't been doing his chores, he's just hanging around the house , growing mushrooms.