Hi, Thanks for writing in. It is important to know if you have any wound in th cervix or cervicitis with cancer of the cervix. There is a possibility that tissue might slough out from the cervix in a patient of cancer cervix. This is more prominent after having sex because there is close contact between the penis and vaginal vault and cervix of uterus in sexual intercourse. Ejaculation is part of sex and the semen is deposited in the vaginal vault. The semen consistency also might be thick and sometimes there is vaginal secretion also during sex which is more in some people. Sex might cause sloughing of some layers from the surface of cervix and this mixes with the semen and vaginal secrtions causing a brownish vaginal discharge which you experience. Suggested discussion with your doctor. Please do not worry.