In such a situation, you should emply a technique that I can best describe as buck and roll.   *Lock your legs around your attackers as best as you can.  *grab one of his arms  *buck, making a kind of bridge with ur body, in the direction of his arm which you grabed  *he will lose blance then role over  *now kick/knee him in the balls (if its a real fight) and get out of there.    Im only an orange belt so forgive my poor instructions. If you want them in more detail, or something doesnt make sense, point it out and ill explain in detail.    Yours,     Marcus