I don't mind them at all if they contribute, and occasionally if they don't but are well done. I don't want to find hardcore porn in a book I'm reading unless I'm reading it for that specific purpose.
Like a few others have said though, it is hard to do well for all types of readers. So I think the safe route is to leave most of it to the imagination of the reader, after all if I wanted it explained in graphic detail I'd just go get a movie - or turn on primetime TV now