If you want this to happen please continue!!!
Step 1: Step1
Get out the snap circuits 303 set and if you don't have it I'm pretty sure you can get the parts you need. You need parts B1 and W1. P.S. this isn't a taser!!!
Step 2: Step2
Put them together as shown. Connect the circuit. If there is no sound (high pitched) turn W1 around and try connecting them again.
Step 3: Step3
Slide your device into the sofa.
Step 4: Step4
Cover it up with a blanket (quilt, bed sheet, pillow, etc.).
Step 5: Step 6
Sit on it, if it doesn't work tweak it. This prank you can play any day and never have too much trouble!