This achievement is story related and can't be missed.
*** Spoiler - click to reveal ***
After unlocking
use the chimney to get to the attic through the right window. Pull the rope from the tied up Dr. Fred, and climb out again. Use the rope on the pulley and go downstairs.
Go outside and use the dangling rope on the mummy.
If you haven't gotten
already, make sure to talk to the mummy first.
After the mummy has been tied to the rope, go through the chimney, and pull the rope.
Again go through the chimney and into the attic. Have Hoagie send you the red paint bucket and paint the mummy red.
Use the red mummy on Dr. Fred lying on the bed. After the cut-scene tie the rope onto Dr. Fred and go out the window.
Pull the rope and after the cut-scene you are in the cellar laboratory.
If you haven't gotten the funnel already get it from the washing room behind the diner room. It's in the pink cupboard.
Also get the regular coffee from the diner room, if you don't have it already.
In the lab, use the funnel on Dr Fred, and then use the regular coffee on him.