Get your crew to show you, hand you, or point to objects in the room. As the people present items to you, freestyle about them. If you run out of things you can point to pictures on a screen or words in a book. Point at a new item every few lines.
This is a great way to show people you are actually freestyling (sometimes you’re so good people don’t believe it’s actually freestyle) and to impress people with your skills. What they don’t realize is that they are making it possible!
Punchline: If you really want to win a crowd, you have to be clever. Don’t just say the name of the item and make a rhyme, like “a knife, a knife, hey, don’t take my life.” Build up a lyrical story about the object, and drop the name like a punchline: “People on my street are out making strife; Walking ’round with a frown or a fist or a knife”. Watch notable freestyle rapper Supernat use this technique. He builds his description, so much that the audience might think he missed the point of the exercise. Then he finally names the object, and pow! Big crowdpleaser.