The main thing to be mindful of, particularly for people suffering with PGP or Symphysis Pubis dysfunction (SPD), is to try and keep your knees in line with your hips. When your knees touch or dip together in the middle, that causes a valgus (outward angulation) stress on your knees. This valgus position of your knee also puts your buttock muscles in their least active state meaning they are then not supporting the joints of your pelvis. The weight of your body, your bump and gravity are then having a bigger impact on your joints because they are not being buffered by your buttock muscle strength. So, popping a pillow between your knees when you are lying on your side will help to take you out of that valgus position and keep your knees in line with the middle of your hip, which will allow your buttock muscle to be more active in your resting position. During the day, if you are out shopping or walking for more than 20 minutes, where a recommended SIJ support belt to limit the build up of strain, which will then present itself at night when you are trying to rest.