mat back 

A promiscuous woman who repeatedly engages in the act of coitus (sex) with many different partners and thus should attach a mattress to her back to increase time efficiency. (so the guy can push her over and fuck her).

Ay, Mortimer! Do you so righteously recall that mat back we double teamed last Friday!

mat back by Norsey September 25, 2007

Matback 

in other words mattress back describes a fat person you can use it for all people like if they are skinny you would say you single matback and if they are fat you call them a double matback

Girrrrrrrrup big matback

Matback by misterrrjosh November 3, 2019

Matback 

Matress-Back, meaning a girl is a "slag" and always has a back to matress doing "the business". Also means that a girl is a prostitute.

1) Bro, that gyals a matback, been with bare mans

2) Oi, did you know Sophie is a matback these days?

Matback by kyasper September 7, 2005