Green’s Dictionary of Slang

blinds n.

1. (US tramp) the false door at the end of carriages; thus places between the carriages where a tramp can hide while riding on a passenger train.

[US]E. Booth Stealing Through Life 7: On the trains we saw no ‘blinds,’ no ‘trucks,’ no steps by which we could climb to the car tops.
[US]G. Milburn ‘A Hard Road to Ride’ in Hobo’s Hornbook 247: So I’m on the blinds of the Flying Crow / And I’m going to ride her through.
[US](con. 1950-1960) R.A. Freeman Dict. Inmate Sl. (Walla Walla, WA) 12: Blinds – the false doors at the ends of a baggage car.

2. (US gay) a foreskin.

[US]B. Rodgers Queens’ Vernacular 222/3: .
H. Max (S)language 5: blinds—foreskin.
Alyson Almanac 60/2: blinds. The foreskin on an uncircumcised penis [Simes:DLSS].

In phrases