My original tumblr post was here. Original text:
http://eroticartrainbow.tumblr.com said:
Artist unknown – (If anyone has any further information, feel free to let us know at: http://eroticartrainbow.tumblr.com/submit). Please include the post number when doing so (see instructions on our homepage).
I can at least provide the source. This is a crop of Ultretomba #253: La quercia dei supplizi (“The oak of torments”).
Image source ComicVine.