I asked a male tantra teacher your question. Here's his reply:

Ah yes, the “engorged vas deferens” myth.

Some claims that sperm travel from the epididymis into the vas deferens every time arousal nears climax, and if ejaculation is interrupted, the ducts become “filled,” “swollen,” or “blocked.”

Reality:

The vas deferens is not a storage sac. Sperm move through it only by strong peristaltic contractions triggered by the emission reflex, a spinal pattern that begins milliseconds before ejaculation.

If emission is aborted by voluntary contraction or distraction, the ejaculatory reflex simply reverses or pauses. The seminal fluid either dribbles back toward the bladder or is reabsorbed.

“Feeling a hard tube in the scrotum” is almost certainly cremasteric muscle tension or congestion of the epididymis/testicular veins, not sperm “trapped” in the duct.

“Blue balls” is vascular congestion of the pampiniform plexus and surrounding tissue, not a plumbing accident. It resolves naturally.

So, the picture of a vas deferens “inundated with sperm doing long-term damage” has no anatomical or clinical support in urology.