== Penis/Phallus == 

 an act which is both an echo of the way that the alien "facehugger" infests its victims,  and a sexual symbol of phallic penetration and rape[  by an android that, even if he did have a phallus (which is not specified in the film) would probably have been sexually non-functional. 

 it seems that phallus is a symbolic image of an erect penis, maybe it should be rephrased to "if he did have a penis" then?