Displaying last TWO largest in a binary search tree???

[IADPCFEVER]

How would I display the last two largest nodes in a binary search tree
recursively???? I don't know how to approach this, and would like some help. Thanks!

[Smac89]

pseudocode:

a = root
b = 0

while a != 0 and a=>right != 0:
    b = a
    a = a=>right

print a
print b