The wall on a new build estate had been pointed with very weak mortar. The customer called us to come and fix it.
It should be done like this
To make pointing mortar, use a standard 4 parts sand to 1 part cement mix for modern bricks, or a 3 parts sand to 1 part NHL 3.5 lime mix for older, historic properties. Combine dry ingredients thoroughly in a mixing tray before slowly adding water until it reaches a workable, crumbly-yet-sticky consistency.