Go to the top of the mountain where the pink rock is.
Get the checkpoint.
Take pink rock.
Suicide off the map (don't touch the floor).
Pick up the pink rock again.

Achievement unlocked.

In Time Trial Mode (no dialoge):

Instantly press "Shift" at the start.
Go near the pink rock.
When you pick it up STOP MOVING!!
When the bird stops twirling, press "Shift" again.
Head towards portal.

Achievement popped up before the end.