This might be way off base, or very personal, when a bump forms on me, that is painful top squeeze, push on, or wear anything that rubs against it, it is a few days after I have masturbated. They form at the tendon area on the inside of my thigh. There is no change between period time and not period time as far as pain goes. It does hurt to move my leg at times. I have used warm tea bags on it. It also happens on the puffy part of my pubic area, when I squeeze it out in that area it is white and stringy like, like a dried up white head. Imagine play dough being squeezed out of a small tube... But generally, its on my tendon area.