Writing sex scenes

It is helpful to know the difference between the following words:

incite and insight

massage and message

prostate and prostrate

played and plaid

ministrations and menstruations(!)

I ... I just ... that last one.

Also, what's with all the "sealing" of eyes? Close is a perfectly good word. If you seal your eyes, I think your eyelids must have some adhesive or something. Like envelopes. DO YOU KNOW WHAT HAPPENS TO ENVELOPES WHEN THEY ARE OPENED? Ripppp. Not good.