Personally, anything shy of "Hey honey, lets bone" goes right over my head, so I find comfort reading these stories, knowing I'm not the only one.
You can't be subtle, either you mount him or he has no clue.
My wife like to seductively Block out 30 minutes on her dayplanner a week in advance. It's hot.
I stand next to him while he is on the computer game and shout SEX!
It started off as a joke about me being as romantic as a brick to the head (we were talking about how being British, we don't have a romantic stereotype) but now I say it every time just to hear him giggle: "Get on your back, you're getting it!" Works every time.
We have a tone of voice we use when we're propositioning. We always ask "so... how you doing?" or "hey". Followed by wiggling eyebrows. Then my husband usually jumps me.