Good question. I had the same injury. I honestly only felt okay when standing. Sitting and laying down were both uncomfortable. Until your symptoms are better, I'd personally be inclined to hold off from sex just because there is a good chance you will not be comfortable. I'm sure you can have mutual masturbation if you so desire and aren't in pain. I was very uncomfortable and feeling 'sexy' just wasn't happening until I healed but I healed relatively quickly (within 2 weeks). Maybe icing it will help heal it quicker? Do you have any problem having a bowel movement comfortably? Here is an overview of this type of injury https://www.webmd.com/fitness-exercise/tailbone-coccyx-injury#1