The yoni egg may come out on its own during or after your practice, or when you get up in the morning after wearing it to bed. Whenever it comes out, just know that your yoni was ready to release it and rest.
If you want to release it voluntarily, you can squat or sit on the edge of a chair with your hand ready to catch the egg, and gently bear down with your pelvic muscles as if you were releasing a bowel movement. (Note that the egg might come out inadvertently when you do relieve your bladder or your bowels, so be prepared to catch it!)
If you are wearing a drilled egg with a string, you can gently tug on the string while doing this pushing. Do not push forcefully, but slowly and in rhythm with your breath, avoid creating any uncomfortable sensations.