Colloquialism for the selector lever on a select-fire firearm or
safety on an automatic weapon, which engages the mechanical safety,
semi-automatic fire, or automatic fire/3 round burst. Switching to automatic fire and putting streams of lead downrange is well known to elicit giggles of joy from anyone who grew up playing video games or watching GI
Joe/The A-Team.
1) Private
Joe Snuffy flipped the giggle switch on his M-249 for the first time, and laughed maniacally as he engaged the
pop-up targets on his qualification range.
2) Rangemaster: "Flip that giggle
switch and give 'er a whirl
Trainee: "heh heh heh . . ." *BRRRRRRRRAP!*