Hello everyone!☺️ I wanted to ask you: What signs did you recognize in…

Hello everyone!☺️ I wanted to ask you: What signs did you recognize in yourself as uterine tone? What sensations should be usual? My belly sometimes feels like a small ball protruding from my lower abdomen and it hardens on touch during the second trimester. This state usually lasts for several minutes a day. I don't know what it could mean.