I know it's silly as f**k but...

[TStyx]

It sits in the actual chest cavity, wrapped around the heart according to A3.

How would it actually get there though coming from the windpipe?  It could only reach the stomach or the lungs and I doubt it could get into the lungs.

[SM]

Pierces the windpipe and injects the genetic material to starting merging with the host and forming the embryo.

[[cancerblack]]

It will no longer need to attach to a creature's face

Where's the fun in that?

[Necronomicon II]

Just give the facehuggers a stinger ovipositor and we have an overpowered beast... It will no longer need to attach to a creature's face, it can inject the egg directly into the host's body!

Well you see, a rapey A.I. wanted to violate orifices, but yes if it were truly natural and bereft of a history of co-evolution with mammals then yes that would make sense. 

[Kurai]

Based on Kane's implantation, I believe the Facehugger can secrete acid if necessary. There was no sign of damage to the Facehugger's body and yet it still melted through the visor and latched onto his face.

I think, if need be, the Facehugger could latch onto a far larger host, like a whale, without the need of an orifice at all. It's within the realm of possibility that it could burn or gouge a hole in its' host and implant its' "material" that way. I think a few creatures do similar things in real life as well.

[markweatherill]

butthole.

Wasn't there a scene in one of the unused Alien 3 scripts, the one with the monks, where this happened?

[JokersWarPig]

This thread needs Jesus

[TStyx]

Pierces the windpipe and injects the genetic material to starting merging with the host and forming the embryo.

Ah I see how that works, kind of like the spores in Covenant then?  David did make the Alien, interesting!