A Straw was the 2nd clue for "Snack Time" and the 1st clue for "The Snack Chart", as well as the 2nd clue for the Blue's Clues & You! episode "Meet Josh!".
Looks
It is a white bendy drinking straw with red vertical stripes. Compared to the other immobile straws, it is small.
The straw that appeared in "The Snack Chart" resembled this straw, only it was smaller.
Gallery
Drawing of the straw in "Snack Time"
Drawing of the straw in "The Snack Chart"
Drawing of the straw in the UK version of "The Snack Chart"
Drawing of the straw in "Meet Josh!"