
Image and text from: Masonry Essentials (1997) by Black & Decker pg 60
Load the trowel with mortar then position the trowel a few inches above the starting point.
In one motion, begin turning your wrist over and quickly move the trowel across the surface to spread mortar consistently.
'Furrow' the mortar by dragging the point of the trowel through the centre in a slight back-and-forth motion. Furrowing helps distribute the mortar evenly.
Note: The Americans call spreading mortar, 'throwing' it and bedding a brick is called 'setting'