Im already pg, but may be able to help.
When I fell pg with Lily I had tons of ewcm on the Sunday. We bd on the Wednesday after and that was when I fell pregnant.
This time around, we bd on the Saturday morning, then the following Wednesday and I am sure I got ewcm on the Thursday (after the Wed of bd'ing).
So, in short, fell pregnant 3 days after bd'ing with Lily, and either 1 day before, or 4/5 days before.
x