@ysmina-- Yea, you can use an orthopedic seat cushion. You just have to put it on your seat and sit on it. It protects the spine and also prevents the tailbone from receiving too much weight and pressure. You should find that your tailbone pain is relieved after using it for some days.
I have a desk job and I sit far too long in the day. I have back pain and tailbone pain as a result. But an orthopedic seat cushion has helped considerably. You might also want to purchase an orthopedic chair for the office. There are ones that encourage the individual to sit up straight.