Green’s Dictionary of Slang

liza n.

[SE lie, i.e. one ‘lies with’ the woman substitute]

(S.Afr. prison) a makeshift hole lined with cloth, used to aid masturbation.

[SA]H. Levin Bandiet 156: ‘Lizas’ – things to lie with. [...] Another bandiet made a hole in the side of a cupboard which he lined with cloth. Another had a special tin-can with a hole in it.