Feels like my ovary is twitching?

I'm on day 6 of my period, it's painless and very light (usually last 7 days). I am sexually active, pull out method. Anyways my right ovary, maybe some other organ is twitching very randomly. It doesn't hurt just noticeable.

A few times a day it feels like my ovary or uterus is twitching..what could that mean?