1 - BONDING WITH YOUR WEAPON
The facehugger is an item. This means that you can pick it up and, most importantly, attack marines with it. However, the hugger can also move on its own and leap at marines from large distances on the right conditions.
DRONES:
Remember that the hugger will only stay alive on your hand for about half a minute. After that, it's dead and useless. To prevent this, drones can take advantage of their ability to carry eggs along. Eggs, unlike huggers, can be carried for as long as you want, but require some time to grow after being planted.
Huggers can also be put back inside (planted) eggs, which resets their death timer. Drones can exploit this to prevent huggers being used for combat from dying.
CARRIERS
Carriers on the other hand can store huggers, as well as eggs. But they still suffer from only being able to hold the hugger for a short time. USING THE THROW HUGGER ABILITY DOESN'T STORE THE HUGGER BACK. To do so, you'll have to drop it and wait for it's sprite to start moving and then use the ability on them.
And, most importantly, huggers don't move for a good while if they're dropped. Just dropping a hugger on a stunned/downed marine won't work; the little guy will only gain conscience and leap towards hosts after roughly 15 seconds (not really sure about the time, but it is relatively lenghty).
2 - USING FACEHUGGERS IN COMBAT
2.1: The Combat Hug
The most common form of using facehuggers for combat. The basic idea is to click on a marine while holding a hugger. However, drone and carrier combat hugging are quite different.
- 2.1.1: Drone Combat Hugging
Drones are the most fit for combat hugging; they're faster than carriers, even more so with frenzy pheromones. Use your nimbleness to hug while the other xenos charge, and transport eggs from the queen's room to the frontline so you can hug more frequently. However, remember that you're weak, so if you misclick while trying to combat hug, get the fuck back before you're shot to death. Find the nearest empty egg, put your hugger in it so it doesn't die, heal up and try again.
2.1.2: Carrier Combat Hugging
Carriers have a harder time running towards hosts and hugging them: they're big fat targets for marines and aren't as easily replaceable as drones. However, a carrier with combat hugging experience can hug many hosts at once and walk out alive, specially if they're elite/ancient. In any case, you're better off staying behind other castes so their captures are hugged faster. You can also take advantage of the Queen's screech or the Boiler's gas to hug as many marines as you can before they return fire.
One particular feature of huggers is that they can leap into a marine from around 5 tiles away when they exit their eggs. A seasoned combat drone will plant eggs in the dark tiles near marine routes (such as LV's Nexus and Red's bar road) and open the egg when a marine walks near. The little hugger will jump as far as a carrier can throw them, but with the exception of instantly latching.
Carriers themselves have the ability to throw huggers (shift click/middle mouse button while holding a hugger), but they have the downside of the huggers having a cooldown before latching into the nearest marine. However, this does not mean the ability is useless: in FOB sieges, it can be very useful if you have a boiler: thrown huggers can pass through cades, so launch them near the marines while the gas is around. That way, until the marines see it, the hugger will have lost it's cooldown and leap from VERY FAR into the nearest marine. And even if they do see the hugger, some of them ignore it anyways.. (works best if you throw it behind a barricade facing south, as it will cover most of the hugger's sprite).
2.3: Carrier Traps
Good carriers are despised by all marines. They'll have traps EVERYWHERE, hugging everyone and everything near weeds. Some tips:
- Make traps under every item or dead body you see. Marines expect traps to be under bodies or items preplaced on the map, but not under guns, helmets and even limbs. Specially useful on LV-624, as the beach always ends with hundreds of items laying around.
- Have a hivelord around when making traps. A single plasma transfer will replenish all your plasma and can be done from afar and while you're moving. You can benefit from this by making every tile around you a trap, even if it's unloaded.
- If you are a good clicker, you can bait marines into your traps. First, attract a marine towards you (easy due to your size and squishyness). Then, quickly make a hole under you and place a hugger. If you gave the marine enough "line", they'll run right into it. Works even with the more experts at finding hugger holes.
- Groups of marines are more prone to falling into traps, specially if they're freshly laid and have a target to shoot at else than the trap.
- You can combat hug a marine even if they're behind a cade, unlike slashing. Just make sure to click their sprite, not the cade.
- Drones can't throw huggers further than a tile. It's just not worth it.
- Huggers are immune to shots while leaping. If you see a marine about to shoot an egg, open it so the hugger can leap. It may not get the marine, but it's worth a try.
- Throwing huggers into cades is a good way to induce FF.
- You will probably die a lot if you try to combat hug.
I'll probably add some pictures if I can (and if I remember to take them)