I just bought some
Madam Sew Heat Erasable Pens on Amazon and they are a game changer! I never tried this product before and I am in LOVE LOVE LOVE! They instantly disappear with the touch of an iron, but the marks are bold and easy to see until you need them. They are gel pens that mark very easily on your fabric, no tugging or dragging.
Just wish I had tried this sooner!