CM egg white or ?

[Indigo89]

So I'm tracking cm as a guide to ovulation. Fertile week on Ovia so DTD but then 2 days later I've had what looks like ewcm. But how do you know it isn't sperm, when you're DTD every other day it's hard to tell.
Anyone else have this? How do you tell?

Sperm flows under UV light.

Glows

Oh yes! I remember seeing this on a hotel programme once x