I started off sleeping with a pillow resting between my legs but now I find that uncomfortable too. I'm now sleeping with two pillows running the length of my body - I wedge one pillow under my tummy and the other one I use to put my whole "top" leg on from the knee down (so if I'm lying on my left side, I draw my right knee up and put my knee and lower leg on the pillow - my left leg is flat on the mattress). I find if I only put my knee on the pillow there is too much pressure put on my knee from the height difference between my hip, knee and ankle.