For me, the goodnight kiss was certainly that, but also a last ditch attempt to engage in sex with my wife. In fact I can't begin to recount how many times I've used the last kiss to get in my wife's pants and succeeded. It usually goes like this: I lean over and give her a tender kiss goodnight, than mumble innocently, "...honey, have you ever considered that tomorrow I may not wake up and this could be our last chance at intimacy?" I usually do my best impression of Bambi on death row when I say that also. I'm not saying it works all the time (or I'd be employing the technique every night) but the last kiss approach works more often than it fails. Or maybe my wife's just been humouring me all these years.
Conversely, the last kiss I had that really made me think I died and went to Heaven was actually the first kiss I gave my wife. We had done the peck-on-the-cheek thing for quite a few weeks. She and I had never really made any overtures to one another that we were in love. I didn't want to tell her that and risk losing her, and she didn't want me to think that she was so old fashioned that she could possibly be interested in a boyfriend. So we carried on this charade of disinterest for a little while until it became physically overbearing. Then one afternoon the kid gloves came off, the truth was laid out by me for her to see, and when we realized how silly we had been we shared that first kiss. An electrifying moment if ever there was one. Since that time I make a habit of letting her know that any kiss we share may be the last kiss for either of us. Call me silly, but I'm not above using a little bit of guilt if it means a bouncing on the bed in my underwear.
The mistletoe kiss is another variation of the last kiss. Useful for those too shy to make the leap toward a potential lover's lips without a visible excuse. Of course, manoeuvring someone under the mistletoe can be a challenge in itself. I used to circumvent that problem by just carrying a sprig of mistletoe with me in my back pocket. That way it's always handy when the opportunity for a kiss presents itself. The last kiss I ever want from my wife would surely be the forehead kiss. You've probably done that to your kid a hundred times or more. In fact, children seem to need the forehead kiss as a sign of reassurance on the part of the parent. From one spouse to another that however does nothing for my self-esteem. Some psychologists claim that the forehead kiss is seen as mock-parental since a mother or father will often comfort a child with a kiss to the crown of the head. And besides, the forehead kiss almost never leads to sex.
I'd be remiss if I didn't include the sloppy wet kiss from a grandmother as another last kiss on my list. There were a couple of times as a child when I worried that grandma's mouth was getting a little to close to mine. A few instances where I thought she was getting a bit overzealous in her display of grandmother-nephew affection. But she was also farsighted, so who knows for sure who she thought she was looking at.
Kissing has always been a symbolic thing in society if not marriage. The last kiss on the lips of your spouse or lover isn't the only one we've come to know and use. Consider the kiss of the hand, kiss of the neck, kiss of the foot. I'm pretty sure they are all symbolic of man's desire to procreate. Or at least do some heavy necking.