OP

Quoted from PinMonk:

I use this method all the time with new games if the lights keep popping out of the spotlights. It works 100% of the time in my experience, and the bulbs never fall out again. It's WAY cleaner-looking than silicone or hot glue, IMO. You can't see anything is different once the bulb is installed. I'm showing a random LED bulb I grabbed to demonstrate this in the picture series, but it works for the LED flashers, too.
You need to cut a small piece of black electrical tape about the length of the bulb, and about half the width the electrical tape comes on the roll.
Then, carefully lift up the two "legs" of the bulb to get them out of the way.
Wrap the tape around both sides of the bulb.
Fold the two raised "legs" gently back down over the tape.
Put the bulb back in the spotlight or socket for likely the last time. It will grab a LOT better and likely never come out on its own from vibration again.