Hello, well. I think this warrants a discussion with your ob/gyn. I hate to say it but being tested for std's may be wise as bleeding after sex sometimes happens with std's. Chlamydia is know to do that, for example. Now that is probably NOT the case but you want to rule it out. Bleeding after sex is not all that uncommon. Something else that could be going on is that your cervix is quite vascular. During vigorous penetration, perhaps these blood vessels are being aggravated and then bleed. This is a common cause of bleeding after sex too. Are you lubricated enough? Vaginal dryness can increase the odds of bleeding. You also want to make sure you don't have any sort of infection. https://www.webmd.com/women/bleeding-after-sex#1 Likely this is something quite treatable or understandable and you don't need to be overly worried. but do get it checked out with your doctor. Let us know what they say!