The reverse mohawk in my opinion-

I looked it up and I'm dying of laughter help

Even better if the man is middle aged and already balding.

Long. Honest to god. Long and wavy.
See fred and george in Goblet of Fire

Yep
Not like really long, just longer than usually and wavy
Especially messy
Messy hair is sexy hair

It depends on the person. You don't want to be hidden in a mop of hair and you don't want to look bald.

You want the hair to be longer on top and a bit shorter around the sides...nice and smart looking :) like this:
http://content.latest-hairstyles.com/wp-content/uploads/2013/09/smart-style-tailored-cut.jpg
Or this:
http://hairstylecamp.com/wp-content/uploads/2015/12/30-Most-Popular-ivy-League-Haircutsfor-Men-2-min1.jpg
none of this man bun shit or fegging rat tail bs!

My crush has the first one
*dreamy eyes*

I mean the man bun works if you have the right hair for it... but the rat tail is shit

Like this!!! XD
http://67.media.tumblr.com/5142661e136bd879a50b5cc827077a84/tumblr_npwy4egS8V1tjusryo3_540.jpg

I'm partial to the classics: http://www.artofmanliness.com/2009/10/27/the-mad-men-guide-to-a-manly-haircut/

i like Fohawks on guys, but i also like long hair on guys

like Evan Breens haircut