Bear-hug Defense 2

The first defense is a simple back-kick to the shin or knee, once the grab happens from the back you lift a foot up and give a hard kick.  The second is a stomp-kick to the lowest part of the shin right over the opening of the shoe. A stomp-kick to the toe of the shoe can possibly work but it's risky the shoe may have enough cushion to absorb the blow.

When grabbed from the side you can deliver a stomp or front-stomp-kick to the leg in front of you hitting the knee or shin. If your grabbed from the front immediately use the stomp to the shin, knee to the thigh or hard knee to the groin.  If your picked up you can still try the stomp or knee strike.  Try to put up to 2 defenses in a combination and practice against anyone of any size.

Bear-hug Defense 1

The first defense is the most simple which is using the headbutt when your grabbed from the front, side or the back and your arms are trapped.  A front grab can be defended by using a quick jabbing headbutt to the face smashing the nose.

When the grab comes from the side you can do a simple sideways headbutt giving a snapping or a throwing strike hitting the attacker with the top or side of the head.  A back grab can be stopped by a backwards headbutt and make sure people you know well don't attack you like this.