I haven't had the chance to use it yet so I am not sure but I think any sort of leaking happens because of a lack of "suction". Apparently the cup is supposed to create a seal when inserted which is why you are supposed to squeeze the bottom of the cup when taking it out... maybe you need a different size/material or simply need to experiment with location and angle. I hope it works for you! Heck, I hope it works for me too haha!