"Bottoms Up" features a "bass-thumping" beat. Nicki Minaj appears in the song as herself, and her alter-egos, Roman Zolanski, and Harajuku Barbie. Minaj delivers her lines as in cartoonish voices and inimitable baby-talk, distorting her voice in parts to sound tipsy. Minaj also sings breathily and references
Anna Nicole Smith, and biblical figures
Mary and
Joseph.
BET Sound Off said, "two of the hottest things in the industry have teamed up for what might be a contender for the hottest joint of the 2010 Summer", commenting, "THIS ish right here is the perfect anthem for happy hour, the end of a hard day at work or even a stressful situation. Maybe it's the pounding kicks that keep my head nodding. Or, maybe it's the infectious hook 'Bottoms Up, Bottoms Up.'" Andy Kellman of
AllMusic called it "shamelessly mindless". Mariel Concepcion of
Billboard gave the song a positive review, praising Minaj's role, stating, Songz' part "fades in to the background" and that "Minaj steals the spotlight with a layered, almost cartoonish 16-bar verse that injects the track with much-needed liveliness and creativity", showing "more personality in 45 seconds than most rappers do in an entire song, balancing an aggressive attitude with her gentler side."
The Washington Posts Sean Fennessey described the song as "gleeful, kinetic" and viewed that Songz is outperformed by Minaj, writing "[she] supplies a brilliant extended cameo on the song, and as she has on nearly all of her guest appearances this year, changes tempo, tone and persona in thrilling flashes". "Bottoms Up" is set in common time with a moderate tempo of 82 and is in the key of
C minor. ==Music video==