Onomatopoetically-themed sex jams are a storied tradition in the R&B game (see just about any random Bobby V. single, for example), but “Boop!!!”? It sounds like the kind of thing you’d say when poking someone in the nose. As the guy who claimed to have Invented Sex, however, Trey Songz is an old hand at making the ridiculous sound hot; on this cut, the latest single off one of two street albums scheduled for release tomorrow, he does it again. Carlos “Los” McKinney and Chef Tone handle production duties, layering sultry synths over slow-rolling percussion as the singer pays tribute to a certain woman’s prodigious assets. Just how luscious is the rear-end in question? Well, when it’s approaching, Songz is reminded of a big-rig moving in reverse: “Your booty like a truck when you back it up on me (Boop! Boop! Boop! Boop!)” If this ode to shapely buttocks leaves you fiending for more, prepare for a double-dose of Trey Songz goodness tomorrow, when R&B mixtape Anticipation 2 and its rap counterpart, #LemmeHolDatBeat 2, touch down on Tuesday, November 1.