Sankaku Channel/semen extraction

Cum is collected from a rather helpless subject in a manner that does not necessitate arousal in the extractor, be they a tentacle, mechanical device or simply the conductor/conductress of a manual milking.
Although masturbation with an onahole is technically also a form of extraction, it is not considered taggable as it lacks the aspect of control over the extractee.

The intended use case are tentacles collecting cum from their subjects.

This tag has been aliased to penis_milking.