This guy I know says that the way to wear cologne effectively is to spray it on the back of your neck, and then run your fingers towards your lymph nodes. He says that when you’re hot, the beating of your pulse in your neck sends off a scent.
This true or not?
That depends on whether or not you really want to emit a scent. I find cologne to be offensive when it’s too noticeable. The best way to wear it is to spray it into the air and then walk through the mist as it falls to the ground, leaving just a very faintest hint of a scent on your person.
The best way to apply cologne is on very warm stops of your body or places that can get very warm. Such places would be the back of your knees, under your wrists and so on. The neck is also a very warm spot so that is why almost all men wear it there.
I can confirm that. I’ve tried both of it, and none of it is the real fun 
Here is how I do it on the rare occasions I wear the stuff, with - I’ve been told - pleasant results. Something I got from a GQ article on the subject a long time ago.
Forget the spray idea. It’s too easy to concentrate too much. Using your finger or a dauber, put a drop on each wrist, behind each knee, on either side of your throat and on the interior side of each upper arm. These are all pulse-points and (somehow) help optimize the distribution of the scent so you don’t have to use much and risk being overpowering.
If you use your fingers, after applying to the areas listed above, run your fingers through your hair as well, without applying any more cologne. It’s a nice, subtle touch as long as you’re not using heavily scented hair products.
I always thought that if I can smell someone’s cologne or perfume without entering their “personal space”, they’re wearing too much. Your scent is for you and your SO to enjoy, not for you to mark your territory by leaving a cloud wherever you go.