As bump notes, this goes a long way toward explaining the disciplinary disparity between blacks and whites in public schools.
bump along with Bill to his newest (and possibly only) dance track in this promo video for GatesLetter.com.
However the breakfast show they were working on has been axed and will be replaced by a show called The bump.
1590s, "protuberance caused by a blow;" 1610s as "a dull, solid blow;" see bump (v.). The dancer's bump and grind attested from 1940.
1560s, "to bulge out;" 1610s, "to strike heavily," perhaps from Scandinavian, probably echoic, original sense was "hitting" then of "swelling from being hit." Also has a long association with obsolete bum "to make a booming noise," which perhaps influenced surviving senses such as bumper crop, for something full to the brim (see bumper). To bump into "meet" is from 1880s; to bump off "kill" is 1908 in underworld slang. Related: Bumped; bumping. Bumpsy (adj.) was old slang for "drunk" (1610s).