So sometimes I start my period at the beginning of the week and it last usually 4-5 days which really sucks cause I see my SO on the weekends and I really can't wait to have sex lol. But, sex and blood is not my thing, neither his. (So I think) when it is done by Thursday or Friday, when we have sex on a Saturday well notice I bled while we had sex. What does that mean? Is it old, does it mess with something? I'd like to know exactly for myself and so if it happens I can explain it to him because he says "I fucked your period back" lmao