This is totally normal! When you use the bathroom, you push down on your pelvic muscles which could cause the disc to shift out of place and leak. It should shift back when you're finished, but if it hasn't just use a clean finger to readjust it back into place.
2. Try inserting in a different position. Everyone's anatomy is different, so you might find that it's easier to tuck the disc behind the pubic bone if you're squatting or standing with one leg up.
3. Try The Thumb Trick! If you haven't checked it out yet, please do! It gives you better leverage and can really help 'lock' your disc in place.