This prompt could go a few ways:
- My little brother has built a fucking machine, but it needs to be tested.
- He needs help designing it. He understands the basic concept, but how fast should it go, and how deep should it thrust? How should the user be positioned, and should she be strapped in?
- He’s afraid no one will understand it by itself. He needs someone to give a live demonstration. In front of everyone at the school science fair.
Other ideas:
- Perhaps my little brother molded, or wants to mold, the phallus from his own penis.
- You didn’t tell me, but you’ve made it squirt with your own sperm.
- The judges (the principal and the head science teacher, genders of your choosing) want to see us and the machine privately before they make their final decision.