inside balls
The short version of something_in_balls
When an object, which may or may not be a living creature, is assumed to be inside testes or scrotum (i.e. balls) of another character. Clues such as ball_bulge, imprints, internal_view, cutaway or text should provide the evidence.
This tag is often used with cock vore, but it can also appear in other urethral penetration scenarios, such as those involving sex_toys or tentacles, or scenarios with parasite or infestation.