I’ve been having sex throughout my entire pregnancy

Just make sure you’re comfortable

No and it can actually help prepare your cervix for labor after 37 weeks. Just don't be too rough and like @kayydoll95 said, you can cramp or bleed after but its only because b the cervix can be irritated by it at times but it's not harmful

No. It's normal. Bt You Can Bleed or cramp After.