I think that Holly hit upon the right combination of factors that would make a man act more like an "animal" on dates. If a woman, straight out, lets a guy know that are certain "rules" for dating her, then many potential dates would never happen. When a guy asked me out on a date for dinner, I said that I would like that but I wouldn't have sex on the first date. If he was interested in me for more than sex, then he would continue to pursue me. Unfortunately, he had other problems and killed himself before he ever asked me out again.
And I had my share of a few men who wanted something for something. Even at work, I became friendly with a boss who soon was telling me I could go very far with the job, and then he showed up at my apartment door. I talked to him, at the door, but did not let him come in. He became very hardnosed toward me after that but he still did not get to first base. I did eventually transfer out of that position so I didn't have to be subjected to him and his "come-ons". Back in 1982-3, there weren't people speaking of sexual harassment but it sure was happening.
Of course men want to have sex whenever and wherever they can, but that does not mean that the woman has to agree. Different sizes or shapes of women, I believe, doesn't make a man more or less ready, willing and eager to have sex. Whether you are shapely or not, your body type and personality attracts certain kinds of guys. If you have already set the game rules, then you shouldn't need to worry about the man trying to get his share of your desserts after dinner and a movie.
Some, not most, men prefer to have a lady on their arm and a pro in their bed. As far as casual sex goes, I think the woman still makes that decision. It is unfortunate that some women play such games and act like teasses, but only the inexperienced man will fall for that. Same is true for a woman going out to dinner and not knowing what to do aferwards if the man expects pay back. A simple goodnight kiss and saying that it was fun should be enough.
I am all with Holly and Sue about intimacy being as important as sex, in the long run. It really has nothing to do with being over-sexed or under-sexed, just that men and women have different needs. Haridas, your question about mechanical versus natural intercourse, IMHO, is that release is just that - release. A man wants the release (and doesn't much care how he gets it) whereas a woman wants to feel "loved", cuddled, embraced, felt needed and desirous".
Sue, I have been married for many years (28), like you and feel like you do about how good a marriage can remain the same after many years. It may not be the same as it was 20+ years ago, but there is an understanding, caring, gentleness and love, as well as alternatives, that keep the marriage alive, happy and satisfied. I would think that open, honest communication of what a person likes and dislikes, and what will be acceptable or not, is the best way for any couple to remain dedicated to and in love with each other.
If we are talking about individuals (or single people), I think it is hard to find companionship and intimacy without sex coming in to play at some time. Saving sex for marriage is the only thing that I have noticed being changed lately. That is just another facet of getting to know somebody. Of course, safe sex always needs to be practiced and all the warnings given about being used and feeling used if the relationship is one sided. The good thing is that if we openly communicate what we each want, we have a better chance of getting it.
For example, if I need to be held while I cry or need to have my back rubbed, I know that I need to reciprocate in a way that will satisfy my husband's "manly", emotional or psychological needs. We all know that there are MANY different ways to satisfy those needs besides intercourse. My husband had a good saying that "every man wants a lady in public but a PRO in the bedroom." It's not very hard to figure out what that all means to each of us, and it certainly might be different for each of us. BUT, I like chocolate and that is a great way to start! Might as well make it a sundae and add some whip cream, too!

Trish
PS I don't use the "F" word in my daily life either, Alex. I agree that it usually shows that a person has a limited vocabulary like you said. Haridas, I might be a hypocrit,too, because I say "FFFReeaking" alot, usually under my breath when I get upset or mad. We all know that is just the substitute for the "F" word.