A exclamation either when the exclamator destroys something or does something wicked awesome.It is usually screamed when something is set on fire or exploded. it is also screamed when somebody does a stunt or a backflip or......something cool......like that.
(throws a 20 pack of fire crackers into a bon fire. this results in large noises and lotsa, lotsa explosions)Random Dude: Boomshackalacka
In the Early 1970's it was discovered that "Boomshuckalucka" was a term that widely described the climax point of anal sex, When one would dispose of his load in/or around the circumference of another mansasshole.
Johny rammed it up there, as if he was a Sailor without a care. Letting him know I was almost there, he felt the urge to boomshuckalucka all over my testicles, Thus having to deal with the uncomfort of them sticking to my leg for the remainder of the evening.
when you're holding up your phone and making faces at it, as though you are taking a selfie, but you're really taking a picture of the person across from you or the wall or anything else that seems interesting but you don't want to be caught dead taking a picture of.
This action is often made more convincing by wiggling the eyebrows or opening the mouth, to pretend you're trying to get a Snapchat filter to work.