Its a candle!
Plants. Say corn for example. It grows and wgen you eat it, it gets smaller
It grows smaller in size.
From smaller size to a bigger size
The joker in me says their brain, but the intellegent man in me doesn't know.
You become weak, this is called atrophy.
Her brain?
When the moon grows smaller, it is said to be waning. This is the period between the full moon and the new moon, when the visible portion of the moon decreases.
it gets smaller as it grows older
cutting down trees etc.
Mount Everest does not get smaller, every year it grows by a couple of milimeters.
You're dick grows smaller
to wane: waned (like the moon grows larger when it waxes and as it wanes it grows smaller.)