Is that an actual mechanic in Metal Gear Solid V? Melee fighting? I'm still discovering lots of things about the game and I know that you can grab from behind or charge someone and put them in a lock but it would be cool to actually fight hand-to-hand or whack them with whatever's nearby be it chair or wooden commode seat cover a la Yakuza.
You can use a series of CQC moves... on the top of my head:
-With your prosthetic arm equipped instead of the pistol, you can run towards enemies and unleash a powerful punch by pressing R2 or whatever key you have for shooting
-In normal stance while standing, press the same button (from now on, R2) in succession to make a combo (3-hit if you're behind the enemy, 5-hit if you're not). Both this and the running punch described above will leave the enemy unconscious for several minutes
-If you prefer, while you're in the middle of that combo you can press the aim button instead (think R2 + R2 + aim) to disarm and hold up the enemy. From there you can interrogate him or tell him to lie down (they will remain like that until another enemy discovers him or youd get discovered). You can also disarm him, release quickly the buttons to drop the weapon and he'll try to use a pistol, where you can try to disarm him again. This is useful for OSP missions where you're in need of a pistol.
-Aiming to them from behind will result in the same hold up pattern described. Be wary because the AI in this game is adaptative, and if you try that too much they'll start countering that by slowly reaching to their knife and counter-attack you. It's easy to spot anyways, and you can always immediately press the interrogation button after holding them up, if the interrogation options don't appear, he's about to strike.
-If you deploy at night, you can use the weapon's flashlight to blind them for a moment.
-When hiding behind a corner/rock/obstacle, you can produce noise to have the enemies' attention. When he's about to get to you, tap the R2 button to make an awesome knockout movement. Or you can maintain the button pressed to hold them.
-If you're inside a container, you can do something similar, pressing R2 when they come to investigate. If they see you entering a toilet, use the quick dive button instead (try this too when inside a box).
-Pressing R2 while simultaneously pressing a movement key will result in a knockdown animation. These tend to be short knockouts, the enemy will wake up quickly, but are useful if you're about to be discovered by another enemy and don't want to sit out the whole brawl animation. The neat thing with this is that you can use it up to 4-5 times in a row to knock down several enemies at once.
-If you're holding an enemy and have a wall/obstacle nearby, you can throw the enemy towards to it by facing the enemy to the wall and using direction + R2
-A personal favorite, if you're running towards an enemy you can use the quick dive button to knock him out briefly. He won't be unconscious but you can aim a gun to hold him down. Very useful if a close enemy discovers you and you want to avoid the alert quickly. If the lad is far from you and you don't want to get any alerts, you can quickly shot him once with a lethal weapon before he gives the alarm, it will give you a couple of seconds to react without killing him.
-If you're above an enemy (on a roof, stairs, whatever), you can use the quick dive button and fall above him. Depending on height, it will render him unconscious or not, but you have a few seconds to react, and it's funny.
-You have an enemy on your shoulders and another fella discovers you? simply use his colleague and throw him towards the enemy
-When prone, you can also press R2. If facing down, Snake will knock them down with the arm, use that time to hold them up. Alternatively when facing up, snake will use his leg (useful after a failed hold up when the enemy strikes you with his knife)
-Some prosthetic upgrades can let you electrocute the enemy, use your arm like a rocket and more.
-Not really CQC, but there are no rules about running over enemies with vehicles, keep it in mind.
-Or calling a supply box on their heads...
-You can fulton a guy, and then shoot the balloon. They'll fall unconscious.
-If an enemy is a level above and needs to go down a ladder, you can get their attention by producing noise, then wait down there in the ladder (they won't see you). Watch what happens when their feet meet your head.
-Another non-CQC move, but too funny not to mention, you can plant C4 in the enemies' backs. Can be useful to solve some objectives as well.
-If a soldier is driving a vehicle, you have a few options; use your horse or another vehicle and hit them to the sides with a well timed bump. Or shoot to the tyres. In missions where you have to catch an objective moving in vehicles, you can use this tactic, they'll have no other option than to traverse the map by foot.