First of all, both cars should be turned off, along with anything else that runs on electricity—your air conditioning, radio, and any GPS devices you have. Leaving any of those on during a jump-start could risk damage from the surge of electricity.
Can a Prius be jump started?
Jumping a Prius or another Toyota Hybrid isn't much different than having to jump-start a gas-powered vehicle. To jump a Prius, you will need jumper cables, an assisting vehicle, and a solid metallic point. Once you have these items, check out Chicago Northside Toyota's guide on how to jump a Toyota Prius.