Do *not* douche. Ever. Unless you are instructed to do it by a medical professional for a particular medical reason.
Douching is known to disrupt vaginal pH by messing with the bacterial flora. It is not a good thing to do. Furthermore, it will not wash out the sperm or keep you safe from pregnancy. You'll need to use protection of some sort to avoid that, and in this case, you may want to consider a morning after pill if it is still within the first 72 hours following the incident.
Hi doucheing ur sopose to do it once a month after a period or u can do t the day after sex if u feel gross down there but it not safe to do it after every sex yal do at least I heard it really wasn't safe for ur body to do it at all but I still do