Green’s Dictionary of Slang

bumper n.3

[ext. of bum n.1 (1) + echoic of the buttocks hitting a hard surface]

1. (US) a trunk.

[US]Daily Trib. (Bismarck, ND) 23 Oct. 4/1: A trunk is a ‘bumper’.

2. (US/W.I.) the buttocks [? play on keister n. (1)/keister n. (5)].

[WI]Francis-Jackson Official Dancehall Dict. 7: Bumper the behind: u. woman, me love yu bumper/ I love your rear end.
[UK]K. Koke ‘Could Have Been’ [lyrics] Pretty face, small waist, big bump-per. / Tight pum, firm boobs in her jump-per.
J. Spades ‘Twerk’ [lyrics] Gyal dem shakin their bumpers / Twerk, twerk, twerk, twerk, twerk, twerk, turn up.

3. usu. in pl., the female breasts; occas. buttocks.

[US]‘Bill O. Lading’ You Chirped a Chinful!! n.p.: Bumpers: Upper front or lower back of a girl.
[US](con. 1944) N. Mailer Naked and Dead 485: What bumpers on her.
[UK]C. Wood Fill the Stage With Happy Hours (1967) Act IV: Couple of sequins on her bumpers.
[US]‘Red’ Rudensky Gonif 102: Babes with big Bumpers Wanted. For Shipboard Duty.
[UK]A. Bleasdale Who’s Been Sleeping in my Bed 48: Those bumpers of hers they’re like the tip ends of torpedoes.
[US]‘Jennifer Blowdryer’ Modern English 77: tits (n): Bumpers.
[UK]J. McDonald Dict. of Obscenity etc.
[US]S. Morgan Homeboy 15: Joe rebounded two feet off the fortyfour triple-D bionic bumpers attached to Bermuda Schwartze.
[UK]A. Sillitoe Birthday 92: But I still like nudging into your front bumpers.

4. (US) the vagina.

[US]G.V. Higgins Cogan’s Trade (1975) 44: I should’ve told her, go out and throw the bumper around.

In compounds

In phrases

bumper to bumper (adv.)

(US lesbian) of lesbians, vagina to vagina, said of dancing or sexual intercourse.

[US]B. Rodgers Queens’ Vernacular 38: bumper-to-bumper 1. tribadism, i.e. rubbing vulvas in a face-to face position ‘Not all gay women do it bumper-to-bumper; some prefer sixty-nining instead’. 2. close, intimate dancing or standing close together, vagina to vagina.