Switchblade

Fallout 2
The blade of this small knife is held by a spring. When a button on the handle is pressed, the blades shoots out with a satisfying "Sssssshk" sound. It's that satisfying it might give you a boner LOL :)

Fallout Tactics
The blade of this small knife is held by a spring. When a button on the handle is pressed, the blades shoots out with a satisfying "Sssssshk" sound.

Fallout 3
In Fallout 3 the Switchblade is a melee weapon that lacks the humourous description of the versions in the earlier games. It affected by the Melee Damage Bonus from Strength.

Locations
Switchblades can be found on random Raiders or Talon Company Mercs across the Wastelands.

Switchblades can also be found:
 * Springvale School, on the upper level, stabbed into the desk with the diary terminal
 * Vault 101, if you kill Butch while escaping the Vault.