Green’s Dictionary of Slang

porch n.

[1980s+] (US gay) the buttocks.

SE in slang uses

In compounds

porch climber (n.) (also porch pilgrim, window climber)

[late 19C+] (US) a burglar; thus porch-climbing.

porch monkey (n.) [monkey n. (4a); the stereotyped image of black laziness, i.e. sitting on the porch]

[1980s+] (US) a derog. term for a black person.