/u/Chainweasel@lemmy.world explains this well, though I got a different take on the analogy.

Imagine you are trying to put air into a deflating balloon that’s about to ‘loose form’ that’s essentially what you are trying.

Put just enough air (energy/mass) into the star and it will stay stable, loosing as much as you put into it.

Too little and the star will dissolved, in this example you’d fully absorb it.

Too much and you are essentially infusing a star with so much mass that it explodes all over again.

If you are trying to stabilise a star this way, ideally, it would never even begin to go nova.