The phrase "guinea pigs" is often used to describe people who are being used to test something new, like a product or an idea, to see if it works well or has any negative effects. Full definition
Trust me when I say that I have used myself and my clients as guinea pigs for the past six years to get to the healthy, vibrant state that I'm in today. (mindbodygreen.com)
The merchandise and monetary award will help us place more rescued guinea pigs in their new «forever» homes. (oxbowanimalhealth.com)
Small animals, such as guinea pigs, also go nuts for it. (petbusiness.com)