i was masturbating and looked down at my fingers and saw a little bit of blood on my fingers. i have short nails. this is not the first time it has happened, probably the third in around a year. i am not a virgin and have sex on a regular basis with my boyfriend and have never bled while he was playing with me or during intercourse. i was wondering if i should be worried and what could be causing the bleeding and what i should do about it?