In the Room the Bottoms Come and Go

I'm reading Jeffrey Escoffier's history of gay porn, Bigger than Life (Running Press, 2009), and it's a good, informative read, but things keep catching my attention. Like this, describing the filming of a famous early hardcore feature, Boys in the Sand:There was no top, no bottom -- indeed those rigid distinctions had not yet evolved among gay men ... [98]Then, a few lines down on the same page