I have my period currently, but I decided to masturbate using my vibrator anyway. All was fine, but shortly after orgasming I found I bled out a rather large blood clot and instead of the usual, dark red that my period normally is the blood was yep, bright red and thinner in consistency. I
put my menstural cup back in (I took it out to masturbate) afterwards.
My first though was that I irritated my cervix a little (if it makes a difference I haven't had sex in a long time) and that was the culprit but honestly I wanted to check with some more knowledgeable people before letting my head get the better of me.