How do I get K pop style men's wavy hair?

Like the casual wavy sort of style like natural looking like texture and layered and stuff...I don't really know how to describe it, but it's like this sort of look: (Yes I know the Luhan picture is absolutely massive)

soompi has a guy's hairstyle thread vv http://forums.soompi.com/en/discussion/132438/hairstyle-thread-for-guys#latest
but to answer your question, the first pic does not look casual wavy at all tbh, it looks like bedhair. it just looks like his hair looks really damaged, so it's hard to say if he even did anything to his hair there. i've had my hair that blonde before and when it's that damaged, your hair can literally be styled without product. 
the second picture, assuming he doesn't have a perm, it looks like they used a flat iron (or curling iron, but flat iron is easier) to create the small "waves" in the hair (you can easily do it by using your flat iron and curling down as you pull through your hair). then it looks like they got wax (or could be any styling product) and scrunched the hair and focused on the roots to give it the volume. 

Thanks for the advice and link to the thread I couldn't find it haha

@JakeZ 
Also here are two youtube videos that I have come across before. 

Mousse and flat iron definitely. Get the Glampalm Signature 1/2" to straighten your sides!

I think that such hairstyles need a lot of special styling too  Can't imagine anyone with such hairstyle which appeared in a natural way! 
I agree with the previous response, you should to use the special iron straightener and also some styling products like here for example http://machohairstyles.com/best-hair-gel-for-men/  I think that it can be a hairspray and wax, or gel, it depends in the certain type of result which you want to get 
I like using gels more of all because they're the most convinient for me but it's very individual in general