The act of jumping in the air whilst screaming, "BOOBSHAKALAKA!" and smacking a female's breasts with both hands, in the manner of dunking a basketball.
Bobby: So how was your date with Helga last night?
Jimmy: Well things got a little awkward when I gave her the boobshakalaka.
Bobby: Damn, that shit is wack!!!
An onomatopoeic "in your face." Originally the sound of a slam-dunk in basketball -- the "boom" being the dunk, and the "shakalaka" being the rattling of the backboard.
Pippen over to Grant ... he shakes and bakes ... to the basket ... BOOMSHAKALAKA! (NBA Jam announcer)