@doddlebobs We've used preseed for a few months now, you use an applicator to insert some right near your cervix so it can mimic CM, its a bit fiddly but we quite like it as I can sometimes be lacking in the CM department! I don't believe the success stories though - we got pregnant first month trying with it but had a very early loss and not a hint of a BFP since (used it for past 4 cycles).
After a quick google re EWCM vs emissions I have found this:
Here are some ways to tell the difference between EWCM (egg white cervical mucus) and Semen
EWCM is stretchy: EWCM (egg white cervical mucus) is very elastic. If you put it between your fingers, it will stretch without breaking apart. Semen, on the other hand, doesnt stretch and will break apart if you put it between your fingers and try to stretch it.
EWCM is slippery and clear: While semen may feel slippery as well, it looks white and cloudy. Not clear, like EWCM. EWCM (egg white cervical mucus) is more transparent and feels very slippery.
EWCM does not absorb easily: If you look at the toilet paper when you use the bathroom and notice mucous on the toilet paper, you can tell if it is actually mucous by waiting a few minutes. If it is semen it will quickly absorb into the toilet paper, whereas EWCM (egg white cervical mucus) generally will sit on top of the toilet paper.
EWCM will form a ball in water: When you go to the bathroom, let the mucous drop into the toilet water. If it turns into a ball and sinks, it is most likely EWCM. If it dissolves into the water, it is most likely semen.
Also I always check my CM first thing in the morning, where we tend to DTD in the evening so I figure most of the semen will have gone elsewhere by the next morning 