Small amount of blood after sex

The past couple of times my boyfriend and I have had sex I've noticed a little bit of blood when i go to the bathroom and wipe afterwards. A very small amount like the amount you would get from a small papercut. The first time it happened was a couple weekends ago when i rode him while drunk and i just figured maybe i was being too rough but didnt really realize because i was drunk. It happened again the next day, same amount.

We had sex again the other day and it noticed it happened again. I notice it coming from the same area (more right side) and same amount every time. But its barely enough to even wear a panty liner for, I'll put one on and there will maybe be like one little spot of blood later but that's it.

These past few times this has happened we haven't used lube. I just had a pap smear about 2 months ago and it came back clean so i dont think anything is seriously wrong (i hope) and also there isnt really any pain other than a little soreness on the outside.

Has this happened to anyone else?