Disclosure: I recently received the Memory Foam Knee Pillow with laminated cooling gel pad and washable cover for free for my unbiased and honest review. The opinions expressed are my own!
I will admit, at first, that I wasn't sure if I could sleep comfortably with a pillow between my knees. I had tried a regular size pillow in the past under or between my knees after arthroscopies of my knees and back surgeries to get comfortable on my sides, without success! I've got sciatica and restless legs. I found that the mats on the sides of the pillow helped with keeping it from getting warm between my knees. The memory foam part of the pillow was quite comfortable, and it didn't feel "squished" to me in anyway. Bridge To Bright Future made the pillow, and they recommended it for those who are post-op from hips and knee surgeries, during pregnancy, and for those with hip, ankle, knee, joint, and back pains. It was comfortable for me! I did notice that I tended to not wake up with it between my knees because I probably change position a lot in my sleep, and it ended up on the bed near my knees! The zippered cover can be removed and washed in cold water and air dry. There is a picture below of it before I went to sleep with it between my knees.
I do recommend this pillow! For more information, you can check it out at : Memory Foam Knee Pillow .