OK - heres my uneducated reply !

Yep EWCM = Egg White Cervical Mucous

TMI - i find i get this when very close to O and also while Oing - starts out as noticeable when wiping then gets to the stage where there is enough to notice on my liner. I have even had enough in the past to have a long string of it from me to the toilet seat and across my hand while wiping (told you it was TMI)
If its clear and you can stretch it between your fingers and it doesnt really break then its EWCM but if its creamy and you can roll it around- bit like clag at school- but not stretch it then its not O time.

Bummer - ddint mean to hit post reply yet !

ETA - leading up to AF mucous dries up. After AF mucous is creamyish and turns into EWCM then becomes creamy again after O then dries up.
(well thats what happens with my weird body anyway)

Somewhere i have paperwork that explains all this really well...