Hello, and I hope I can help you today. Masturbation is not normally physically harmful, but if you penetrate yourself with a hard object you can actually scrape or cut yourself in the vagina. If you are close to your period or it just finished, there also can be some additional blood released from the uterus from the contractions caused by orgasm. I your case since the bleeding is only on the right side, I think it is most likely you have a small injury inside your vagina. It is important to let the area heal completely, so I would avoid putting anything inside the vagina (no tampons, fingers, intercourse or sex toys) for at least a week, or when the bleeding stops, if that takes longer. In the future, I would try to use objects designed for masturbation and a lubricant to avoid chafing or injuring yourself further. I hope I was able to adequately answer your question today and that my advice was helpful. Best wishes, Dr. Brown I hope I was able to adequately answerr