What Causes Vaginal Bleeding After Intercourse?

Hi, ma I answer your health queries right now ? Please type your query here...hi im 19 years old and after intercourse i wiped and there was a spot of blood. I put a sanitary towel on and theres now pinkish spots of blood. There isnt alot at all. This has never happened before. We had sex three times in the space of 24 hours