Unless you think sex allows your partner to steal your vital life essences
Bingo (though I don't think women necessarily steal your essence, more so that men just lose it. That's not to say that some women can't steal it, however
). Ever wondered why men are often so knackered after emptying the proverbial tank? Well, this is actually a pretty big topic, but as a rule I would say; As men we do have finite amounts which can be released without having an impact on overall vitality. I think that when in a loving relationship, there is more of an exchange of energy as opposed to just a loss on the mans part. I think that loveless sex may fulfill an anatomical need, but is just a waste of energy. So I endorse ilmae's analogy, well played sir.
I would also agree with the others, that politely approaching strangers in the street isn't unacceptable. As Rui said, the main things are that your respectful, are receptive to how open a person might be to it, and can take a hint effectively. As long as you have these things down, then it shouldn't have to turn into one of those "err this is awkward/creepy" moments.
Have to say, it's not something I've done frequently though, mainly because I don't really ever get a strong desire to chirps a female based purely on looks when there isn't some aspect of her personality I'm infatuated with too. I guess you could sort of say I've done it on a couple of occasions though, but it was only once I'd received "the look", and I then approached with some semi passable opening convo. I actually ended up being in a relationship with one of those women (met a train station) for a few months. It is very,
very rare for me to do that kind of move though.