I've been rolling with some Gracie Barra guys as of late. a white belt(six years of training on and off) a blue belt and a purple belt. It's been great fun and good way to learn. But when I'm rolling with the blue belt(the only guy im actually able to put in mission control) I get the hand to the mat, clear the neck, and as soon as I put the arm back, he sucks his head to the mat opposite side of the leg. I dont know what to do after he does that. please help!