Does it enter through the rear-end?

After seeing the image of the creature (which I assume is the cobra-hugger) flying out of Milburn's mouth I started wondering "how does it get inside him in the first place?". I don't think it simply goes inside his mouth and then flies back out the same way, that doesn't seem very creative or shocking. So what other orrifice could it use to enter a human (male) body? Only one answer... The ass. Yep. I said it first and I'm completely serious about this. It may slither onto his arm, wriggle into his suit and then enter into him through the anus. Ridley scott did say that there are disturbing scenes in this movie which he is slightly embarrassed to speak of. I don't think he was only refering to Shaws scene with the squidy. Giger would be proud.