I just picked up a rare lot of 6 "Tijuana Bibles". These were cheaply produced, 8-page stapled booklets from the 1930s-40s featuring the pornographic adventures of cartoon characters, politicians, mobsters and anyone vaguely sexy who stumbled into the public eye.
TBs were the Depression-era equivalent of the celebrity sex-tape, so turn your monitor towards the wall and enjoy "Betty Steps Out" (WARNING: Not even slightly worksafe...feeelthy in fact.)
This one is pretty well-drawn for the form. Since all of the characters (besides Betty) look line-for-line like their overground counterparts, I'm betting some tracing was involved. If your browser isn't showing it large enough to--ahem--read use the magnify function or download to your desktop.
This one and five others (including: Harold Teen, Fred "Killer" Burke, Moon Mullins) are available from my store here.