How do I get the grain of sand?

Hint 1 of 7:

If you haven't found the grain yet, look in Colossus's right eye (from your
perspective).

Hint 2 of 7:

You'll need to find a way to hold his eye open to get that grain.

Hint 3 of 7:

Use the toothpick (you can find it by using the loose tooth) on the eye and
go into the eye to get the grain.