Oops! This image does not follow our content guidelines. What sixteen year-olds write nowadays on the sneak in study hall and post later on at night to Wattpad would have landed you a jail sentence in the mid-1960s. People just were not used to reading it, so it took a while and a new generation to find it acceptable. By the mid-70s it was present but did not become popular till the mid-80s. Even after the changes in '68, it took a while for explicit sex to start showing up in American books. but more like an Everyone-rated book that fades to black after a little bit of making out.
They were nothing like today's books, even the ones on Wattpad, because explicit porn of any kind was illegal up until 1968 in the USA and you could go to prison just for possessing it. Gay porn books have been around since the 1950s but you had to go buy them at 'dirty book stores' and the sale of them was restricted to adults only.