Its not dangerous. But it can trigger contractions. In fact, they suggest sex to help induce yourself. It never brought on labor for me with my four, but I did bring contractions. So no worries.
Will for sure make you contract, but your fine unless your doctor has told you otherwise
Baby will come when ready. I was having sex 39-40weeks pregnant and 3cm dialated and still didn't go into labor. Just had bad contractions that kept me up all night lol