Foam Roller Squats can be a good way to practice squats. This will help you prepare for Mālāsana position. If you feel any pain when practicing this you should stop immediately. This should feel safe and comfortable. I recommend synchronizing your breahth with your movement in that you inhale for four seconds as you descend downwards, and you then exhale for four seconds as you ascend back up.
Try to move as much weight away from the foam roller as possible - so you're merely touching it with minimal force.
If you feel pain or tired, take a break and work on something else - or maybe just go do something relaxing. Sometimes it's better to take a break then overtrain. Overtraining can lead to long term irreversible damage.