Hello, and I hope I can help you today.
Believe it or not, it is actually possible to injure your vagina from frequent intercourse. You can develop cuts or scrapes on your
cervix or vagina that can bleed very heavily as area has a lot of vascular flow, especially during arousal. You may have been bruised in the back of your vagina the last time, but now there is a possibility that you actually may have lacerated or cut yourself.
If the bleeding has stopped then at this point all I would recommend is not resuming intercourse until you have an evaluation at a gynecologist office. If you are continuing to bleed heavily, especially, if there is bright red blood, you may need to go to an emergency room as sometimes these types of injuries to the vagina require stitches for control.
Regardless of what happens, I recommend that you and your boyfriend abstain from intercourse or other vaginal penetration (and do not use tampons for the bleeding either) for at least two weeks after this episode. You also should avoid heavy high impact exercise. Your vagina needs time to heal. Also you have to remember that your vagina is only 10cm deep on the average, so with force, penetration beyond this depth can genuinely cause
injury.
I hope I was able to adequately answer your question, and that this advice was helpful.
Best wishes, Dr. Brown