Follicle uses tangentU and normal

Follicle vs tangentV.png
The locator in the image uses the normal and tangentV of the surface as its aim axes. The axes indicator represents Maya's follicle, and you can notice the slight difference between the two. It could be a matter of preference, but the default behavior of a follicle is to use tangentU as its secondary axis.


References

Maya matrix nodes - Part 3: Matrix rivet