Newbie Alignment and subdivision question

[weirdgyn]

how can I align one shape 'face' to those of another shape without deforming both shapes? Up to now I simply get the X, Y or Z coordinate of the face I wish to align to then I do an absolute move (checking 'moving object') of the matching face in the shape I wish to move. The result is good but I hope there's a some more easy and speedy way.

If i understand right:

( a ) Select the face to be aligned
( b ) Left click in Face|Put On command
( c ) Click on the target face and right click to Execute

Only in some cases not in general. I try to be more clear using an example. Let's say I have two cubes of different sizes. I need to align one of the face of the smaller cube with a specific face of the larger cube. Put-on will just put the smaller one on the center of the target face of the larger one... I'm attaching an example with both. Green cubes what I need red cubes result of put-on procedure.