Go to pub and use extendible duck-hanger with the garlands.
In the restroom use screwdriver with the vending machine and take some condoms.
Then go to Randal's apartment. Exit his room by window, go on to stairs and one floor down. Steal a pie.
Back inside, leave the building and go to Emerson Express. Take one of the cones from the street.
Go to Matt's place and talk with vendor. Convince him to swallow some helium. Then talk with the kid.
Chat again with the vendor (about the kid), and when he puts the pipe into his mouth, turn on the valve. The vendor will faint.
Try to take the balloons, but the kid won't allow you to do this, so use condoms with bottle of helium.
Now go to the alley (next to the vendor stall) and from the box (on the right side of the door) take a party blower.
Go near the psychiatrist's office and pick up a cigarette. Use it with the pie. Go inside and use the cone and party blower with Robert. Show the garlands, extra sensitive balloons and a birthday cake to receptionist.
Go to the office and talk with psychiatrist.