Bleeding while masterbating?

Please give some inputs, theories, etc. Has anyone ever bled when masterbating? Usually only happens if i use a toy, but it only happens sometimes. The blood is not like period blood (and it definitely isn't my period), it's more of like a bright, ketchupy looking red and texture. Sometimes it's only a little, sometimes it's a lot. I think i might be hurting the inside of my vagina, or possibly hitting my cervix. Please help - does anyone else have this??