Scervo, you shouldn't be bothered at all by using these techniques, the mechanics simply force you to do it. Sure dealing damage without hitting people with the tip might be unrealistic, but hardly much more than being able to block any stab by leveling your weapon in front of you horizontally and being able to walk through an extended sharp stick, which is why people get to facehug you all the time in the first place. In case you didn't know, it doesn't work like that in real life. Pikes reigned supreme in melee warfare, so the functionality in cRPG is rather limited compared to reality anyway. If someone gives you shit, tell him to stop abusing the bullshit downblock mechanic.
On to stabbing at close range. What Johammeth said is correct, there is a part of the animation where you will deal very low damage. I specifically say low instead of no, because when using a very high damage stab or when stabbing at someone without armour, you stop glancing much earlier in the animation. The trick is to skip this part by missing your opponent and then moving it back into him for the damage dealing part. I'd say the damage dealing part starts about halfway the animation, depends on how high damage your stab is so it's best to just practice a lot and get a feel for it.
Now this missing and then moving back into your opponent has gotten more complicated since they have been messing with turn speed. It used to be the case that any stab could hit at any reach by just wiggling it inwards from the left or right side of your opponent, which is what Johammeth explained. With lower turn rates, say anything below ashwood pike, this has become really rare or impossible, depending on the armour of the target. Turnrate is calculated with a formula using length and weight. You cannot avoid the low damage part of the animation and turn it back into someone from the side at facehug range with a longspear, because the turning isn't fast enough.
Turn rate only affects horizontal turning speed though, which means your vertical speed is completely untouched. Which means that with a longspear you can miss your opponent by aiming over his head, and then dragging it back down to hit his head and not glance. It takes some practice but it's possible to pull this consistently, fighting any armour. You got to practice it a lot though to be able to do it quick enough. Remember though that is does actually do much lower damage than a proper range stab, although this gets partly remedied by hitting the head, and looking up quickly greatly obscures your vision and might lead to not seeing certain threats coming for a split second or missing your opponent because he moved. Another difficulty that can be removed by either using a only stab weapon or using inverse attack direction is that to do an up-down stab, you first have to move down to select the stab, then up, then down again, which is a little awkward.
Here's an example of me doing a close range stab with an ashwood pike + shield. You can see here and in the rest of the video that I don't continously purely stab up and down, sometimes I use side stabbing or diagonal stabbing and what not. Because of the disadvantages of up-down stabbing mentioned above, I try to stab in a way that will allow me to hit while maintaining good vision and also do some confusing wiggling. Basically more turnrate on your weapon and more distance between you and the target means that you don't need the fast turning from vertical movement as much. At max reach stabbing straight is good enough, medium reach just requires sideways movement and close reach a combination of up-down and sideways movement. You gotta learn the full up-down stab though for the real facehug situations and the kickstabs, which are an amazing tool.
Understanding the theory is important, but practice is key. Practice to get the proper timing with all weapons and practice to get it to proper speed. If I pull of a good up-down stab I can prevent getting spammed by pretty much anything even when using a longspear, you gotta really nail it though when it comes to left-swinging steelpicks. People will often go for the spam hit, and that is when you punish them with a quick face stab. Then they whine about it and say it's bullshit, even though it's their fault for thinking they can attack again after getting blocked.
Oh, notable exception is the pike. It cannot stab at facehug range as it simply has no hit detection for like the first 2 feet of the pole (fun fact: this allows you to stab straight through any objects which are less than two feet thick, including teammates, gates and walls).
