Like Sir Mix-A-Lot, we’ve never lied about liking big butts. And we’ve always listened to the 69 Boyz and let everyone see the way we tootsie roll. That’s why we were first in line when we heard about the new monthly booty-bumpin’ party Rumpshaker! at Common Ground (85 Harvard Ave, Allston, 617.783.2071). Host MC Beat Train brings the same excitement from his legendary Cheap Thrills a Go-Go “sexadelic dance party” to this night of “the dopest old-school hip-hop, the freakiest superfunk bombs, and the illest booty-bumpin’ party classics.” Beat Train promises to play only the purest, funkiest music from 1976 to 1992. We’re sold, and so are our mini jean cutoffs. The event is 21plus, and things kick off at 10:30 p.m. Cover is $3.