I'd really rather use my imagination - it seems to work very well in this context!
There was an item on Woman's Hour last week about the Bad Sex in Literature awards - very funny. I am sure, as someone else has said, that editors encourage a bit of titillation and far more detail than the author might originally have chosen.
I also get slightly irritated that an otherwise excellent book (particularly - at the risk of being branded sexist - that is written by a man) can have gratuitous sex scenes that really do not connect to or add anything to the plot. They just seem to have been added for the benefit of the author or editor.
There are lots of things that most authors do not feel tempted to include in detail (e.g. bowel emptying/sanitary protection - use of/c;cleaning the shower etc.) because we all know what it entails and do not need the detail. Sometimes these things, and sex scenes, might usefully be included in more detail, but only when they further the plot or the understanding of the characters.
Glimpses of stocking indeed - that is where my OH came in! He still waxes lyrical about the girls in his class when he was a teenager and the wee glimpses that brightened his day!