Male or futa ejaculation, the expulsion of semen through the shaft of a penis. The use of the tag implies that the picture tagged with it depicts the moment immediately after the semen is projected out of penis so it's clear where it came from, and that the aforementioned penis is seen within the frame of the image.

Use the female ejaculation tag for female ejaculations.
See also: projectile cum

This tag implicates cum.

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