Green’s Dictionary of Slang

skin adj.2

[1950s+] (orig. US) featuring nudity; usu. in the context of pornography.

In compounds

skin bar (n.)

[2000s+] a striptease club or public house that offers strippers.

skin flick (n.)

[1960s+] a pornographic film.

skin house (n.)

1. [1970s+] (US) an establishment providing pornographic entertainment.

2. see also sl. compounds under skin v.1

skin joint (n.) [joint n. (3b)]

1. [1940s+] a nightclub or bar with young women employed to entertain customers.

2. see also sl. compounds under skin v.1

skin mag (n.) (also skin book, ...magazine, ...rag)

[1960s+] a pornographic magazine.