Unfortunately there is not too much you can do about constant rolling. As they are learning what to do & it's all part of the development. Charlie at almost 8months has only just started rolling from his tummy to back after he is sick of being on his tummy, but will still cry out at night if he wakes on his tummy. It is frustrating when you pop them on the ground & they roll then cry & so on. I found this was around the time he started to want to sit up, so I would sit him up with pillows around him, or sit him in his highchair with toys or in a walker. As for sleeping to stop his legs getting stuck out of the cot I just started using a sleeping bag & this has worked well. HTH.