HideHim.swf hides everything except his penis, which works with some backgrounds (gloryhole, girl-in-a-box, etc). That's not really what you asked for, though.
There's also the DialogueActions command [HIDE_HIM], which makes him invisible. Although if you move her to where his penis would be she still somehow sucks it sometimes. It's used in the intros and scene transitions in a few dialogues.
I should probably say that the last person to
request this did it in a way that made it sound like they were intending to sell SDT, and wanted to make a "demo" version - they asked for a version of the title screen that didn't have Konashion's name, etc.