While being quite close to the line, this image is not explicit enough to warrant rating:e.

Following the guidelines in howto:rate, this seemed to be the applicable section: "Actual intercourse, if portrayed in a restrained and tasteful manner". Nothing is blatantly exposed, and the focus is on the act, and not the explicit anatomical details, hence I believe that rating:q is the appropriate rating.

CountPacula said:
While being quite close to the line, this image is not explicit enough to warrant rating:e.

I disagree. The image may be pleasant and tasteful, but it is still explicit erotica. Both parties' bodies are on full display, with the point of genital insertion being fully exposed (albeit mosaic censored).
That is most certainly within the guidelines of rating:e.