Why you could consider advertising your adult jobs at "Lust Jobs"
http://www.lustjobs.com ?
Yes, it is a youngish website, but hey - it is free and can help you out to deliver your message (+ with every advert allows you to get a backlink) as it already ranks really well without any efforts, just well prepared and optimised.
Regards,
Helmuts Meskonis
Lust Jobs