Reddit user uteruinestench described what happened to her next, and it's totally BRUTAL:
IDIOTICALLY, I asked him to help me remove it so we could continue. MOTHER OF GOD... it smelled like an eviscerated decomposing body mixed with rotting broccoli, sewage, and rotting eggs ALL IN ONE. And the smell DID NOT GO AWAY. I threw out the cup and its contents, but the stench of 14 day old rotting blood and uterine gunk is not one that fades easily. I could tell my squeamish boyfriend was trying extremely hard not to lose his shit and vomit. But it only got worse from there.