Implantation bleeding

When does this happen when it does?? Is it a darker color or light? I've never experienced this but I had intercourse a week after my period which is when I ovulate and a day or two after had a tiny amount of blood on the darker side which def wasn't left over period bleeding and have never bled after intercourse before. EDIT Just read it's 6-12 days after conception so had to just been a weird thing