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)
邮件由 firstname.lastname@example.org 发出。我们决不会发送垃圾邮件。