Slight Bleeding During Pleasurable Sex

While changing positions with my partner or right after sex, we have noticed I bleed a small amount on their penis. At first I thought this was because I was about to start or just ended my period, but it happened again when I had sex no where near the state or end of my period. It seems to happen when I'm experiencing pleasurable sex and the size of penis does not matter. I'm confused. I've done some research and some women have claimed to bleed a little when they orgasm but I'm not sure if this is normal?