Why aren't you training your neck, Veeky Forums?

Neck, calves, forearms. High volume, high frequency.
These muscles are at the ends of your body and as such they greatly depend on your genetics (bone thickness/circference). If you wanna grow these, you gotta hit them every day, aim for at least 1000 reps total for each muscle group.

My neck is as thick as my head due to the fact I make hilarious faces as I lift.

After benching I used to get neck cramps from frowning so hard.

How do I get abs to pop on my neck?

I never realized how pathetically untrained my neck was until I started training it

I grew my neck to like bugenhagen levels of thicc and I've never trained it specifically.

I've run this program for a while now and my neck just sort of grew over time. My progress was:
>Bench: 65lbs -> 265lbs
>Squat: 95lbs -> 355lbs
>Dead: 135lbs -> 485lbs

I've done this push/pull for like 2 years now I think.

Push:
>Bench
>Squats
>Incline or Weighted Dips
>OHP
>Shoulder Flies
>Any tricep isolation
>Weighted Crunches

Pull:
>Deads
>Wide Grip Pullups (Lat pulldowns when I was weaker)
>Reverse grip barbell rows
>Close Grip Chins
>Facepulls
>Any bicep isolation

My neck is full chadmode and I have never isolated it.

You probably have forward head posture with a little bit of rounded shoulder/upper crossed

This means your lower cervical spine is flexed forward but to maintain your eye level your head is extended at the c1/occiput joint

Work on strengthening lower cervical extensors while stretching suboccipital extensors in addition to stretching superficial cervicalflexors and working on deep neck flexor exercises (supine gentle chin tucks) to develop better segmental stability

His neck is an average lifters neck...

It's thicker than his head.

you got it the wrong way around.
train extensors (look up and behind) and stretch flexors (the ones on front)
basically do neck hyperextensions either free or with little weight, while stomach down. and look up and to the sides to stretch the front

I'm gonna start training it today.
measurement is 38.5cm slightly above adam's apple