The possibility of pregnancy is not particularly related to whether or not you wash after intercourse. Washing the vagina and vulva after intercourse will only reduce the chances of pregnancy, but it cannot be avoided. If the sperm is of good quality and you happen to be ovulating, you will be able to get pregnant. If you are not ready to have children and you are worried about pregnancy, you can take emergency contraceptive pills, which can be taken orally to achieve 80% of the contraceptive effect. At the same time, you can buy an early pregnancy test about 12 days after intercourse to rule out the chances of pregnancy.