Peas in a Pod
Two players start a scene where they immediately mirror each others body language and copy each others sounds, gestures and mannerisms. It will create two characters that are very similar to each other, like they are best friends and have known each other for a long time.
You can also play it with throwing in regular phrases like “totally totally”, “yeah yeah yeah” etc to strengthen the agreement between the two.
A fun way to find character on stage by playing with your scene partner.