How to follow straight lines with brushes?

[Simon]

Hello,

I want to apply/use the brushes (Any BMP tool) to follow straight lines.
I know it is possible pressing shift key but I get 45° steps and I want to know how to avoid such restriction.
What am I missing?

Thank you

[Hoogo]

Release the shift key while you still press down the mouse button.

[Simon]

Great!
Thank you...