Sankaku Channel/facehugging

Facehugging is taking control of the subjects respiratory and/or visual system by engulfing its head.

It is usually performed by a facehugger, although those may focus on other orifices as well.

The purpose is to subdue and arouse/calm the victim through visual deprivation and injection of aphrodisiac or sedative substances either as aerosol or via the digestive system by means of penetrating the throat.
To this end, the facehugger may take the form of a breather or deepthroat the subject

Facehugging does not refer to the hugging of a cock with the face.