Question for co-sleepers!?

have any other co-sleeping parents had problems with baby wiggiling down? my son has starting wiggiling down a few inches at nite. mainly because we swaddle him and if we dont he does this (spaz hands) hand/arms jerky thing and wakes himself up. he's not moving down far and we both wake up when he starts doing it and move him back up any ideas to help or should i start moving him to his crib? he almost 3 months and i coslept with my other and he never did this. HELP!?!?!